Jeff Zimmerman and I have done lots of work on player aging curves in the past 12 to 18 months. Jeff started things off with a series of hitter aging curves, which focused mostly on standard outcomes and WAR components. Jeff and I then joined forces this year for a series focused on pitcher aging.

This time around, I wanted to know how a hitter’s plate discipline changes over his career. We already know plate discipline statistics are easily the most stable, year over year. That said, I wondered whether I’d see meaningful patterns as players age. Often times, scouts and commentators mention how a hitter’s approach changes over time: less disciplined, less contact as a young player; better bat control and better strike-zone awareness as a hitter matures. But does the data confirm this thinking?

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Before all our attention is focused on the post-season, I thought I’s take a quick look back at free agent signings from the past year and how those deals worked out in 2012. The focus here is just on what teams got for their money. In other words: Did the players meet or exceed the expected value of the contracts they signed?

I focused on major league signings only, so the analysis does not include myriad minor league deals — many of which resulted in players accumulating playing time in the majors this year.

To get a sense of the how the deals turned out, I compared players’ expected values — which are based on their positions and the annual average value (AAV) of their contracts — to their actual values. I uses Matt Swartz’s research on the differences in dollars per Wins Above Replacement (WAR) by position, rather than assume an average dollar-per-WAR, as is typically done.

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There are rate stats for just about every kind of opportunity a hitter faces in a game. Batting average tells you how often a player reaches base via a hit. On-base percentage tells you how often a player avoids making an out per plate appearance. But what about swings as opportunities?

Last year, I played around with the idea of production per swing. The idea was to examine what hitters gave the most value when they took a swing. The methodology was pretty simple: calculate the Weighted On-base Average (wOBA) each hitter generated using their swings — instead of plate appearances — as the denominator*.

Of course, there is a healthy correlation between actual wOBA and wOBA per swing (.83 in 2012), but less so Isolated Power (ISO). (wOBA/swing and ISO share only a .53 correlation.) Some of the results may not be all that surprising, but many certainly are.

Let’s first look at the top-25 so far this year:

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As I was flipping channels last night I managed to stumble on the Padres – Dodgers game. Andrew Werner, a 25 year-old rookie making only his third career start, was on the hill for the Padres. It only took me a few pitches to determine I should stick with the game for a little while.

Although the Dodgers would eventually win the game in extra-innings, Werner pitched a great game as his final line can attest to (6 IP, 8Ks, 1BB). And although he posted an equally dominant performance in his previous game against the Atlanta Braves (6 IP, 7Ks, 0BBs), the way he went about shutting down the Dodgers was quite different.

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We’re only three days from the expansion of major league rosters. On Sept. 1, all players on a team’s 40-man roster will be eligible to play in the big leagues without an accompanying move. Often times, baseball fans are treated to a sneak preview of teams’ top minor league talent as a result of September call-ups; or they’re surprised by a relatively unknown player who manages to contribute over the season’s final month.

In preparation for this year’s roster expansion, I thought it would be interesting to look back at the greatest-ever September call-ups, defined here as players that made their major league debut during the month of September.

There are, of course, two ways to look at this: The first is to look at players — position players and pitchers — who generated the most value for their clubs during their call-up. The second is to look at players whose careers began as a September call-up and then went on to have great careers.

I’m looking at both. Read the rest of this entry »

Updated: Thanks to the commentors, especially Evan, for double checking my work. I had an issue in Excel that messed up the results for May and June. Charts have been updated.

For most of 2012, the Baltimore Orioles have been playing over their heads. Well, at least when it comes to their expected win-loss record.

Based on the run differential the team has generated, the O’s have amassed 10 more wins than we would expect based on their Pythagorean winning percentage. The team has outplayed its cumulative expected winning percentage throughout the year and — since April — picked up two additional wins at the end of each month. If they sustain this performance and finish August with at least 10 more wins then their Pythagorean winning percentage would predict, they would be just the third team to do so since 2001 (the 2004 Yankees and the 2007 Diamondbacks are the other two).

Some might point to this glaring discrepancy between Baltimore’s actual winning percentage and Pythagorean winning percentage as evidence that the Orioles cannot sustain their winning ways. Of course, this raises the question of whether we really gain anything from a predictive standpoint heading into September if we focus on a team’s expected winning percentage rather than their actual performance.

The answer based on a review of the past decade seems to be no.

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Last week, I wrote about some findings regarding in-season fastball velocity loss and how experiencing a loss in different months affects a pitcher’s chances of finishing a season with diminished pitch speed. The general takeaway was that June and July were the most telling months.

But what about velocity gain? We know that, generally speaking, pitchers lose velocity more than they gain it. So while velocity loss isn’t good, it’s to be expected — and starting pitchers seem to be able to deal with that loss better than relievers. Pitchers who can stave off velocity loss (year-over-year change between +/- .5 mph) perform even better. Moreover, if a pitcher gains at least 1 mph on their fastball in a season they are twice as likely to maintain some or all of that gain the following year.

Gaining velocity, while not a guarantee of better performance, is certainly a boon to a pitcher and his organization. But given that velocity varies for all sorts of reasons, when can a team have confidence that the increase they’re seeing is real and sustainable?

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I’ve written quite a bit this year on trends in pitcher aging, specifically velocity loss and gain. In the last iteration I focused on the odds of pitchers gaining velocity back after a season where their fastball dropped by at least 1 mph.

In that piece I listed a few pitchers to keep your eye on given that their velocity was down from 2011. In June, I wrote about CC Sabathia for ESPN and noted that the big lefty is likely beginning to “age”, as the odds are quite a bit higher that pitchers over the age of 30 do not gain their velocity back once they’ve lost it.

After thinking about it a while it occurred to me that there is of course the chance that these pitchers will gain their velocity back by the end of the year (as I noted in both pieces). We know that, generally speaking, pitchers gain velocity as the season goes on. Temperatures rise, and so too do fastball velocities. If this is the case I wondered at what point in the season we can say with greater certainty that a pitcher is throwing as hard as he is going to throw. Is there a particular month where a velocity decline is more likely to translate to or predict a full season velocity decline?
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With yet another day to go before actual baseball returns to the field, I thought I would take a quick look at some of the potential MVP candidates in both leagues based on the first half of the season.

Identifying MVP candidates is certainly not a straightforward process, nor is the criteria universally agreed upon. Knowing this I will not begin or end this article with any claim to have identified the “proper” candidates. These are my candidates based on my way of looking at the term “valuable”.

So what is my criteria? Well, I like to think of MVPs as players that provide an exceptional amount of production in both an absolute and relative sense. This means identifying players that lead or are close to leading the league in production, but where there is also a sizable gap between their production and that of the second best player on their own team. This means that I do tend to discount great performances by players that happen to share the same uniform as equally great players. Is it their fault? Absolutely not. In fact, those players could likely be the best all around players in the entire league. But when it comes to value I think there is a relative component that should be considered. This isn’t to necessarily give credit to the player (i.e. they don’t “step it up” to make up for the gap in talent on the team), but rather to the performance itself.

Like I said, this is my criteria and I don’t claim that it should trump all others, nor would I say it is complete on it’s own. Rather, I think it’ a useful starting place.

Okay, enough with the preamble. Let’s get to the data.

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Eric Seidmen wrote an interesting article last Thursday about Atlanta reliever Craig Kimbrel’s historic strikeout pace. So far, Kimbrel is sporting a blistering 42.7% strikeout rate (K%). Even for a relief pitcher in this era, that’s incredibly impressive. But one person who commented on the story noted that there was a non-reliever approaching the same level of whiff greatness (i.e. > 30% strikeout rate).

Nationals phenom Stephen Strasburg has thrown 182 innings in the big leagues and has struck out 32.5% of the batters he’s faced. No starting pitcher who lasted any significant amount of time ever finished his career with a strikeout rate higher than 30%. The closest  is Randy Johnson and his 28.5% strikeout rate. This season, Strasburg has a 33% strikeout rate. If he were to maintain that pace, he’d be the 10th starting pitcher in history to achieve the feat and would have the 23rd such season since 1916. But take a look at that list and you’ll note that the oldest instance came back in 1984.

The problem we run into with strikeouts — like many statistics in baseball — is that the playing environment has changed over time.

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