Tired of being pigeonholed as a reliever, Aaron Heilman has demanded a trade from the Mets, as he wants them to find a team that will give him a shot to return to his roots as a starting pitcher. Other teams have found success moving relievers back into the rotation, Ryan Dempster being the most recent success, and Heilman was a first round pick as a starter in 2001, so there will probably be a team out there that believes that he’s worth a shot as a starter.

How successful will the conversion be? First off, let’s try to determine how good of a reliever Heilman has been.

Over the last four years, Heilman has tossed 357 innings, walked 131 batters, struck out 322, and allowed 29 HR, which adds up to a 3.67 FIP. That’s solidly above average for a reliever, but doesn’t make him a true relief ace. However, he wasn’t consistently above average all four years.

From 2005 to 2007, he ran a K/BB rate of between 2.61 and 3.15, showing good enough command of his fastball/change-up combination to throw strikes while missing a decent amount of bats. He sustained a pretty low HR/FB rate, which helped him keep the ball in the yard even though he’s not a dominant groundball pitcher. His FIP for those three years was 3.34, and he was a very good setup man.

Last year, however, his walk rate went through the moon, jumping from 2.09 to 5.45, and his HR/FB rate spiked, causing him to be a bit home run prone. It could be random variation, where he just had a rough year finding the strike zone, but a quick look at his pitch selection reveals an interesting change – Heilman started throwing a lot more sliders last year, throwing them in 12% of his pitches versus just 0.4% a year prior. The change-up dropped from 37.9% to just 24%, as the slider made him more of a three pitch guy and less dependent on the change.

The slider may have helped him miss a lot more bats, but he got those gains in strikeout rate by throwing way too many pitches out of the strike zone, and the end result was a jump in walk rate that was more detrimental than the jump in strikeout rate. If the rise in use of the slider was the cause the of dramatic jump in both BB and K rates, it appears to have been too detrimental to be worth it.

It will take a full breakdown of Pitch F/x data for us to determine whether the slider was the cause of the command problems, but it seems likely that the rise of the slider usage wasn’t a coincidence.

What does this mean for Heilman as a starter? Well, there aren’t that many successful starters who rely on strictly a fastball/change-up to get by. Almost every starting pitcher has some kind of breaking ball that they can use to change the plane of a hitters eye, and if Heilman just can’t command his slider, that could be a real issue in moving him into the rotation.

As a fastball/change-up guy, he was a very good reliever. As a fastball/change-up/slider guy, he was something of a mess. It’s not enough to conclude that he doesn’t have a chance as a starter, but I’d call this a buyer beware situation.

Last night, David announced that FanGraphs is officially carrying wOBA as our newest statistical addition. For those of you who have read The Book, you’ll be familiar with wOBA, but for those of you who aren’t, here’s a brief introduction and some reasons why you should give this new, funny sounding stat a try.

First off, wOBA is a linear weight formula presented as a rate statistic scaled to On Base Percentage. Essentially, what that means is that average wOBA will always equal average OBP for any given year. If you know what the league’s OBP is, you know what the league’s wOBA is. Usually, league average falls in the .335 range – it was .332 last year, but offense was down around the game in 2008, which may or may not continue.

So, why should you care about wOBA? What makes it better than OPS or any of the more famous rate statistics that measure offensive value? The beauty of wOBA lies in linear weights. Essentially, every outcome has a specific run value that is proportional to other outcomes – a home run is worth a little more than twice as much a single, for instance. What wOBA does, as all linear weights formulas do, is value these outcomes relative to each other so that they are properly valued.

OPS, as you probably know, significantly undervalues the ability of a hitter to get on base. It treats a .330 OBP/.470 slug as equal to a .400 OBP/.400 slug, when the latter is more conducive to scoring runs. wOBA gives proper weight to all the things a hitter can do to produce value, and is a more accurate reflection of a hitter’s value.

For a practical example, let’s look at Ryan Ludwick versus Hanley Ramirez. Ludwick had a .966 OPS versus a .940 OPS for Ramirez – not a huge difference, but one most people would consider significant. If you put a lot of stock in OPS, you’d probably argue that Ludwick had a better offensive season.

However, Ramirez actually had a slightly higher wOBA, .403 to .401. This is due to the fact that Ramirez posted a .400/.540 line compared to Ludwick’s .375/.591 mark. Ramirez’s 25 point advantage in OBP was slightly more valuable than Ludwick’s 51 point advantage in SLG, and wOBA reflects this.

The other great advantage wOBA has is that it’s extremely easy to convert into run values. Simply take a player’s wOBA difference from the league average, divide by 1.15, and multiply that by how many plate appearances he got, and you have a run value above or below average for that player.

For instance, using Ramirez, who we already said had a .403 wOBA, which is 72 points higher than the 2008 NL average of .331. 0.072 / 1.15 = 0.063. 0.063 * 700 = 43.82 runs above average.

wOBA – league average wOBA divided by 1.15 times plate appearances = runs above average by linear weights. Simple, easy, and accurate. This is the joy of wOBA.

If you want a solid, context-neutral statistic that values hitting properly, wOBA is a great place to start. Some of the other great stats here on FanGraphs, such as WPA/LI and WPA, take context into account to add or subtract value based on how a hitter did in certain situations, but there are times when you just want to know how a batter did at the plate, regardless of who was on base or what the score was at the time. For those, wOBA is the perfect answer.

There are a few things that come every winter – Chrismas, cold weather, and Brian Sabean signing a free agent over the age of 30. It never fails, as the Giants GM continues to believe the best way to rebuild is to bring in players who are heading towards the end of their careers. So, it’s tempting to look at the report that the Giants have signed Edgar Reenteria to take over at shortstop and think that this is just more of the same, but let’s take a closer look at his abilities anyway.

Renteria was a huge disappointment in Detroit last year, hitting .270/.317/.382 and posting a .308 wOBA just a year after a huge season in Atlanta. The big culprit was the loss of 62 points off his batting average – as a guy who doesn’t walk a lot and has gap power, he can’t afford to hemorrhage that many hits. At 33, such a significant drop off is the kind of thing that ends careers. However, there are reasons to think that Renteria’s got something left in the tank.

For starters, he’s one of the most consistent line drive hitters in baseball. For the last five years, his LD% has never been lower than 22.2% or higher than 23.3%. Predicting Renteria’s line drive rate is perhaps the easiest thing to do in baseball. In fact, his batted ball profile was – across the board – almost exactly equal to his career averages. Check this out:

GB%: 2008 – 45.8%, Career – 46.2%
FB%: 2008 – 32.0%, Career – 31.0%
LD%: 2008 – 22.2%, Career – 22.8%
IFFB%: 2008 – 8.5%, Career – 8.0%
HR/FB%: 2008 – 7.1%, Career – 7.4%

That’s some pretty remarkable consistency. If you can find why we should believe that Renteria fell off a cliff in ’08 in that batted ball profile, you’re a better man than me. Even the projection systems that don’t care at all about batted ball data, and just use the results of the last three years (such as the Marcel projections published here on FanGraphs) don’t believe that Renteria is finished.

His Marcel for 2009 has him projected as a .285/.345/.417 hitter, good for a .336 wOBA. That makes him, essentially, a league average hitter while playing shortstop. That’s not easy to find and quite valuable.

However, there’s the issue of how well he plays shortstop. His offense wasn’t the only thing slipping in 2008, after all. The +/- system from the Fielding Bible has Renteria dropping to -9 plays last year from -1 the year before, with his range going from average to a real problem. At 33, we wouldn’t expect Renteria to still be the same defender he was 10 years ago, so this shouldn’t be a huge surprise.

However, even if we project him as a -10 run defender at shortstop in 2009, his league average offense still makes him a +2 win player compared to a replacement level shortstop. Given a rumored price of $9 million per year for two years, the Giants are essentially paying $4.5 million per win on a short term deal, which is about what free agents were going for last winter.

For San Francisco, this isn’t a bad deal – they get a guy who should rebound and re-establish some value without any long term risk, and they fill a hole with an average player while waiting for the kids to develop.

This is also yet another sign that perhaps the 2009 market isn’t going to be a very good one for sellers, as we’ve seen no evidence of any price inflation in the transactions completed so far. The buyer’s market continues.

Scott Boras is known for his ridiculous assertions in an effort to boost his client’s worth on the free agent market. We’ve already talked about his hilarious Oliver Perez as Sandy Koufax argument, so today, we’ll look at his claims that Jason Varitek’s defense is so valuable behind the plate that he’s worth “Posada money”, or about $13 million a year.

The heart of Boras’ claim is that Varitek has a significant, positive influence on Boston pitchers, far more so than any other catcher, and this influence directly translates to wins on the field. He presents the ’08 Red Sox .608 Winning Percentage with Varitek behind the plate versus just a .524 Winning Percentage when he didn’t start as evidence. It doesn’t just stop there, however – if you look at the pitching performances in those respective games, there’s a massive difference.

In games where Varitek started behind the plate, the Red Sox pitching staff had a 3.94 FIP. In games where anyone else started behind the plate, the Red Sox pitching staff had a 4.80 FIP. That’s a pretty striking difference, and FIP is obviously a better measure of the team’s pitching than winning percentage. So, is Boras on to something in regards to ‘Tek?

Maybe, but the macro view of the two statistics just presented don’t help us find out. There’s all kinds of problems with using the data just presented as evidence that Varitek helps his pitchers, starting with the fact that games started by Varitek isn’t a representative random sample. He caught all of Josh Beckett’s 27 starts, 30 of 33 Jon Lester starts, and 27 of 29 Daisuke Matszaka starts. Of the 89 starts made by the Red Sox top three starters, Varitek caught 84 of them. Of the 73 starts made by the various #4 and #5 starters that Boston cycled through, Varitek only caught 36 of those.

If the Red Sox hadn’t performed better with ‘Tek behind the plate, it would have been a massive upset. When 70% of your starts come with one of the big three on the mound, it’s a virtual lock that the team will have a lower ERA with you behind the plate than when you’re not, simply due to the talent level of the pitchers that you’re catching.

So, instead of looking at the macro approach, let’s look at how each individual pitcher fared when ‘Tek was catching compared to when Kevin Cash was behind the plate. There were some huge dropoffs among some pitchers when Varitek wasn’t catching.

David Aardsma: 3.33 FIP w/Tek, 6.71 FIP w/Cash
Hideki Okajima: 3.13 FIP w/Tek, 6.06 FIP w/Cash
Julian Tavarez: 3.06 FIP w/Tek, 5.62 FIP w/Cash
Craig Hansen: 3.76 FIP w/Tek, 6.08 FIP w/Cash
Jon Lester: 3.64 FIP w/Tek, 4.60 FIP w/Cash

On the other side of the coin, the swings weren’t as large, but perhaps more interesting.

Mike Timlin: 6.37 FIP w/Tek, 3.48 FIP w/Cash
Bartolo Colon: 4.54 FIP w/Tek, 3.37 FIP w/Cash
Clay Buchholz: 4.86 FIP w/Tek, 3.90 FIP w/Cash
Daisuke Matsuzaka: 4.12 FIP w/Tek, 3.80 FIP w/Cash

Three starting pitchers did better with Cash than with Varitek, while only one did better with Varitek than Cash. If Varitek really was significantly better at calling pitches and helping his pitchers improve, wouldn’t that be manifest most strongly with the guys he prepares with ahead of time, rather than the ones that come into a game without much notice?

Still, though, the sum difference of the FIP by the pitchers that Varitek and Cash had in common was +.252 when Varitek was behind the plate. That’s a huge difference, worth about 28 runs over a full 1000 inning catcher season. If we could actually prove causation, and not just correlation, Boras’ argument for Varitek wouldn’t be all that crazy after all.

Unfortunately, we just can’t. We just don’t have precise enough tools to judge whether the performance fluctuation can be credited to Varitek, or if it was just random variation. So, while there is some evidence that the Red Sox pitchers did quite a bit better when he was behind the plate, we just can’t say with any kind of certainty that it’s a sustainable skill that will go with him wherever he plays in 2009.

Buyer beware – if you pay a significant amount of money for Jason Varitek’s catching skills, hoping that your pitching staff will magically improve, you’re betting on a hope.

It’s too early to proclaim anything definitively, but a look at the transactions that have occurred so far this off-season reveals a pretty interesting trend.

Jeremy Affeldt signs with Giants for 2 years, $8 million

This is probably 50% of his true value. Worse relievers got four year deals a year ago.

Ryan Dempster signs with Cubs for 4 years, $52 million

This is a pretty significant discount for staying in Chicago. Dempster took the same contract Carlos Silva got a year ago despite being a far superior talent.

Athletics acquired Matt Holliday from the Rockies for a collection of question marks

Holliday was expected to be traded for a pretty hefty package of talent, but there are real concerns about both of the young players Colorado got in exchange for their best player.

Yankees acquired Nick Swisher for a collection of barely useful role players

A year after getting traded for the best pitching prospect in the White Sox system, they turn around and sell him for a fraction of what they paid to get him. Even if Swisher never returns to previous levels, the Yankees didn’t give up much to get him.

Nationals acquired Scott Olsen and Josh Willingham for barely useful role players

While I don’t think all that highly of either guy Washington acquired, they still traded two young players with some name value and got practically nothing back.

Along with the Marlins dumping Mike Jacobs because no one wanted him and an underwhelming market for Coco Crisp, so far nearly every transaction of the winter points to this being a pretty significant buyer’s market. In basically every move so far, the acquiring team has given up less than we would have expected to either sign a player or acquire one in trade. The cost of bringing in talent has been dampened significantly over prior years.

Perhaps this will all change, and the big contracts for the big stars will reverse the course, but right now, this winter looks a great time to be a buyer. Sellers are finding it hard to get anything close to what used to pass for market value. Perhaps we shouldn’t be surprised, then, that Billy Beane is on a mission to collect big league talent right now. Have proven veterans become the new market inefficiency?

This came up in the Coco Crisp trade thread yesterday afternoon, but I felt like it’s worth a larger mention. It’s one of the things that I see repeated frequently among fans and analysts alike, but it just lacks the validity of it’s claim. I’m referring to the notion that a player who is moved from an up the middle defensive position to a corner defensive position loses a significant amount of value – you’ve probably seen this stated as something like the following:

“David DeJesus is a very good center fielder, but his bat makes him just an average left fielder.”

These kinds of statements are mostly due, in my opinion, to the rise of metrics that compare players against an offensive baseline of other players who play the same position. Since the average hitting LF is significantly better than the average hitting CF, moving a player from CF to LF will make him look quite a bit worse. He’s now getting compared to a better crop of players, so his relative ranking falls.

The problem, however, is that the relative drop in offensive value is almost entirely offset by a relative increase in defensive value.

Let’s look at LF/CF, for instance. Last year, major league left fielders hit .269/.344/.442, while major league center fielders hit .268/.334/.420. Over a full season, the offensive difference between a corner OF and a CF equals about 12-14 runs. Over that same full season, the defensive difference between a corner OF and a CF equals about 9-10 runs.

The net difference in moving a quality defensive CF to a corner OF spot will be a loss of somewhere between 2-5 runs, thanks to the decreased amount of opportunities that CF will get playing in a corner. Of course, if you replace that CF with another CF who is significantly better with the glove, you can get those runs right back by getting the premium defender more opportunities.

We really need to get over this idea that guys like David DeJesus, Carl Crawford, and Ichiro Suzuki lose a significant amount of their value because they’re not playing center field. The difference in their value in CF vs a corner is pretty small, and there are many cases where it certainly makes sense to have a premium defender in an outfield corner.

We have to get away from this notion that a good defender is wasted in a corner. It’s just not true.

I promise, you won’t hear about this again.

I’ve been nominated for a $10,000 scholarship thanks to the writing I’ve done over at USSMariner.com, which is strangely decided by popular vote. I’m in second place, about 700 votes behind the leader, who has leaned heavily on Daily Kos for his votes. The fact that I’m still without shouting distance after their full court press for him is pretty remarkable.

Anyway, voting closes tonight at 3 AM EST, so if you’re so inclined to vote for me, you can do so now. I probably need 3,000 to 4,000 votes today to overtake the current leader, so every vote counts.

Thanks for your support.

Batten down the hatches – I’m writing about another Royals trade. Hopefully, this thread goes better than the last one…

According to Sports Radio 810 in Kansas City, the Royals have acquired Coco Crisp from the Red Sox for reliever Ramon Ramirez. Let’s break down both players, win value style.

Crisp has a pretty well established set of skills – He’ll post a BB% around 8%, a K% around 16%, and an ISO around .120. This is the classic groundball/gap power hitter, and not surprisingly, his results are consistent with what we expect from that skillset. He turns 29 in a few weeks, so he’s in his prime, and we shouldn’t expect much of a change going forward.

The Marcel projections has him projected .269/.333/.392 for 2009, good for a .321 wOBA, compared to a league average of .332. This pegs him as a below average hitter, but not a terrible one, worth about ten runs less than an average hitter over a full season. Of course, the Royals aren’t acquiring Crisp for his bat, but for his glove.

The +/- system has Crisp all over the board the last three years: -7 in 2006, +26 in 2007, and -2 in 2008 as a CF. He’s almost certainly not the best defensive center fielder in baseball, but we can’t ignore the fact that he was universally praised as a terrific defensive CF in 2007 and the numbers backed it up. If we just average the three years, we get +5 per year, which makes Crisp an above average CF. I can buy that.

Center fielders also hit worse than league average as a group, so we have to add a positional adjustment of 2.5 runs.

-10 offense, +5 defense, +2.5 position adjustment, +20 replacement level = +17.5 runs, or about 1.75 wins. We probably need to dock Crisp a few runs because of his weak arm (+/- just covers range), so let’s call it +1.5 wins instead. That’s Crisp’s 2009 value, making him a slightly below average player, but still a decently valuable member of a roster.

The Royals didn’t get him for free, however – let’s look at Ramon Ramirez, who was one of the Royals best relief pitchers last year. He posted a 2.84 FIP in 70 innings by racking up a strikeout per inning and, more importantly, not giving up home runs. He only allowed two long balls the whole year. That’s very unlikely to continue going forward (even the best relievers can’t sustain a 3% HR/FB rate), and Marcel projects his HR rate to climb from 0.25 HR/9 to 0.71 HR/9, which is the main reason it projects his FIP at 3.76 going forward.

A 3.76 FIP is great for a starter, but just average for a reliever. You can get a 4.50 FIP from a replacement level reliever, and so over a projected 60 innings, you’re looking at a difference of 5 runs between Ramirez and a replacement level reliever. We have to multiply those five runs by 1.5 to account for the extra leverage of the situations he’ll likely be used in, but even still, that only makes him a +.75 win pitcher.

The Royals clearly got the better player here, turning a decent but not great reliever into an almost league average center fielder. The fact that Crisp is owed $5.75 million for 2009 while Ramirez won’t make much makes this trade less of an outright steal for Kansas City, but Crisp is still more of a value than Ramirez is.

That doesn’t make this a bad trade for Boston, necessarily – they didn’t have a full time job to offer Crisp, and so they turned a superfluous bench player into a solid enough cheap reliever. But this is more of a lateral move for the Red Sox and a pretty decent step up for the Royals.

I give the edge to Kansas City in this one.

Nothing against the Jeremy Affeldt signing from yesterday (that was a great deal for the Giants, by the way), but we have our first notable free agent signing of the winter. Well, it’s actually a re-signing, but it still gives us a pretty good insight into where the market for starting pitchers might be headed. Ryan Dempster re-signed with the Cubs for a guaranteed 3 years and $38 million and a player option for 2012 that could make the deal worth $52 million over four years, if he wants to exercise his option.

Really, though, the Cubs have put themselves on the line for 4/52 for Dempster, since they don’t control the option, so that’s what we’ll call the contract.

Dempster was certainly outstanding in 2008 – his 3.41 FIP ranked as the seventh best mark in the National League, sandwiched right between Ben Sheets and Johan Santana. That’s some pretty solid company for a guy who had been a rather pedestrian reliever the two years prior. He elevated his game by cutting a walk per game off his BB/9 and elevating his strikeout rate simultaneously, leading to a career best 2.46 K/BB rate. His improved command helped him control the strike zone in ways he never had.

However, the real key to his run prevention was keeping the ball in the yard. His 0.61 HR/9 rate was 8th best in the NL, putting him in a group with guys like Brandon Webb, Derek Lowe, and Aaron Cook. They limit homers by inducing a ton of groundballs, but Dempster is not an extreme ground ball pitcher. He leands towards the GB side of the spectrum, but not nearly to the same degree. He just got more than his fair share of flyball outs, which is represented by his 7.7% HR/FB rate. That kind of performance isn’t sustainable over a long period of time and should be expected to climb in future years.

If we bump his HR/FB rate up to 10% (which is basically league average) for 2008, he’d have given up 18 home runs, four more than he actually gave up. Each home run has a run vlaue of about 1.4 runs, so it’s fair to say that we can expect a regression in Dempster’s home run prevention to cost him about six runs from his ’08 value. Even if he maintains his new found command, he’d still be a bad bet to repeat his 2008 season.

But that’s the beauty of this deal for the Cubs – they’re not paying him like they expect him to repeat his 2008 season. At $14 million per season, they’ve essentially valued him as a +2.5 win pitcher, which would translate to a 4.25 FIP over 180 innings. In other words, they’ve built a regression of almost a full run per nine innings into Dempster’s expected performance, based on this contract.

If Dempster really did establish a new level of performance in ’08, this is going to go down as a massive steal for the Cubs – they’d be getting an all-star pitcher for the same price that Carlos Silva got last winter. He can take a pretty sizable step back and this still would be a positive value contract. Essentially, for this to be a bad deal for the Cubs, Dempster’s going to have to get injured. If he stays healthy, this looks to be a big winner for the north side club.

Perhaps one of the more enigmatic pitchers on the free agent market this winter is A.J. Burnett. When he signed his $55 million contract with the Blue Jays three years ago, people derided it as a disaster for a headcase with injury problems. However, after a couple of solid seasons where he mostly avoided the disabled list and pitched pretty well, the contract became too much of a bargain and Burnett opted out in order to get a bigger paycheck this winter.

How much should teams spend for Burnett’s future, though? Let’s go through the calculations one more time.

Thanks to the new Marcel projections that were just added to the site last night, we can estimate Burnett’s 2009 performance pretty easily. Marcel projects him at 187 innings with a 3.87 FIP for next year, but we’ll round that to 190 innings and a 3.90 FIP just to make the math easier. Once again, we’re going to use a 5.50 FIP as replacement level for a starter and cap his innings at 160, and use a 4.50 FIP as replacement level for a reliever, who will make up the 30 inning difference. So here are the totals that we’re projecting:

Burnett: 190 innings, 82 runs allowed
Replacement Level Starter: 160 innings, 98 runs allowed
Replacement Level Reliever: 30 innings, 15 runs allowed

We’re projecting the replacement level pitchers to allow 113 runs, or 31 more than what we’re projecting for Burnett. That would translate to +3 wins for whoever signs him. We can once again add a bit of a bonus to account for his extra innings saving the bullpen, so let’s call Burnett a +3.3 win pitcher.

3.3 wins * 5.5 million per win = $18.15 million in projected 2009 value. We again factor in a 10% discount rate to make up for the fact that he’s going to get a long term deal, and that gives us an annual average value of $16.4 million. Given Burnett’s history, it’s unlikely he’ll get more than four or five years. That puts his projected contract at 4 years/$66 million or 5 years/$82 million.

Those numbers match up fairly well with what the rumors have pegged his price tag at. It seems unlikely that Burnett will be either a huge bargain or a big albatross this winter.