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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Ever since it opened in 1999, Safeco Field has been a horse, and hitters have been mosquitoes. No matter how much the hitters have tried to inflict damage, Safeco has hardly even noticed. Now, ever since it opened, Petco Park has been a whale to the hitters’ mosquitoes — they haven’t even ever interacted — but just because Safeco wasn’t the most pitcher-friendly ballpark doesn’t mean it hasn’t been an extremely pitcher-friendly ballpark, and now, as announced Tuesday, the dimensions will be changing. The Mariners will bring in the fences in an effort to make the ballpark more neutral.

The planned alterations, of course, have been welcomed by the hitters, and they haven’t been condemned by the pitching staff. Fans, too, are pleased, as baseball fans in the Northwest have grown weary of low-scoring ballgames. People want dingers, basically, and Safeco hasn’t allowed enough dingers. The changes should make for more dingers. Yet just what sort of effect will there be, really? When discussing the changes to Safeco Field, one might keep in mind last offseason’s changes to Citi Field in New York.

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2012 was to be a critical season for the Seattle Mariners, as the organization hoped its young talent would start to jell and suggest the possibility of a playoff bid in the near future. Outside of Felix Hernandez, the keys were assumed to be Dustin Ackley, Jesus Montero, and Justin Smoak. All three position players have recently been tippy-top prospects, and all three position players got their own Mariners team commercials. Ackley was billed as a hitting prodigy, Montero was advertised as the new guy with tremendous power, and Smoak was shown punching down trees with raw strength. The season’s almost over — really! it’s gone so fast — and Montero has a -0.2 WAR. Smoak has a -0.2 WAR. Ackley has a 1.8 WAR, but a lot of that is good defense, which, take that, minor-league scouting reports.

The breakthroughs have come from Kyle Seager, John Jaso, and Michael Saunders, which pretty much no one expected. The three guys thought to be most important have all been disappointments. But with that in mind, check out what happens when you sort the September leaderboards by wRC+:

1. Justin Smoak, 195
2. Joe Mauer, 187
3. Chase Headley, 183
4. Adrian Beltre, 180
5. Ian Desmond, 173

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Likely waiting tastefully until the Talk Like a Pirate Day celebrations were in the rear view mirror, longtime Pittsburgh (and short-time Seattle and Atlanta) shortstop Jack Wilson, who was released by Atlanta back in August, is reportedly going to retire after the season. The first thing I think of when I think of Jack Wilson is how I used to always get him mixed up with former teammate catcher/outfielder/first baseman Craig Wilson. Remember when the “Wilson Brothers” and Jason Bay were part of a future Pirates contender? Good thing those miserable days are over. HOKA HEY.

Anyway, Jack Wilson’s reputation was based almost completely on the very good glove he displayed in his prime. Yeah, there was that 2004 season in which he hit .308/.335/.459 (103 wRC+), made the All-Star Game, and people talked about it being a “breakout” year for him. Actually — and I can’t believe this happened to a guy who walked in under four percent of his plate appearances — it looks like that was probably mostly random variation. That was Wilson’s only major-league season with above-average offense, and his career line is .265/.306/.366 (74 WRC+). Despite this, his glove made him a valuable player in his prime, and that was what one should really focus on when thinking of his career.

However, even a glove-first shortstop will manage some big hits over 5,339 plate appearances. So, in honor of his impending retirement, let’s use the story stat, Win Probability Added (WPA), to look at three of Jack Wilson’s biggest hits in terms of their in-game impact.

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In a recent article discussing the latest crop of international talent, valued commenter “Nate” offered a great, concise preview of soon-to-be international free agent Kyuji Fujikawa, who’s presently playing in the Nippon Professional Baseball league:

Kyuji Fujikawa – Closer for the Hanshin Tigers. Closest thing Japan has had lately to a Mariano Rivera-type. He’s 32, but will be a full free agent, so won’t require a posting fee. Expensive teams that forgot to buy a bullpen should look at him *cough* Angels *cough*.

And Nate is correct many times over; not only does one of Japan’s best relievers appear ready for a jump across the river, but he also has every chance to be an elite reliever in the United States.

Take a look at his numbers in Japan:

This is legit. And he could make for a talented addition to a number of teams in 2013.
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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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Felix Hernandez’s perfect game on Wednesday was a testament to both his excellent stuff, but also a well-deserved outcome for an excellent game plan executed by he and catcher John Jaso. A former Ray himself, Jaso appeared to know just how to approach the Rays lineup, getting increasingly good results as the game went along:

That’s 5 swinging strikes through the first 61 pitches, and then 19 through the remaining 53 pitches. How did Felix do this? He and Jaso took advantage of an aggressive Rays plan by placing filthy breaking stuff further and further from the zone.
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The 2012 MLB season began with a very public bounty of international talent — Japanese stars, Cuban expats and even a Taiwanese surprise. With the season dipping into its final six weeks, we are beginning to see both the good and the bad of these international players who made the direct transition to MLB rookie.

SP Yu Darvish — The biggest star from Japan since Daisuke Matsuzaka has had a very Daisuke Matsuzaka season — much despite steady predictions of the opposite. Well, actually, he has an 86 FIP-minus and 94 xFIP-minus. That’s at least a better FIP than Daisuke’s rookie year, but an identical xFIP.

Dave Cameron has written extensively on Darvish lately, noting Darvish has a command problem, the league has realized Darvish has a command problem, and Darvish has a scary group of command problem comparables.

At the same time, though, Darvish has been adjusting his approach to a less-aggressive (compared to the NPB) league. He has been toying with his repertoire, and I would not be surprised if he entered the 2013 season with a streamlined pitch selection that sets up his elite slider (one of the best in the league) more effectively and simply.
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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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Two players I have always rather enjoyed — Ichiro Suzuki and Hideki Matsui — are in the twilights of their careers. And not only that, they are both having relatively miserable seasons at the plate.

At present, Suzuki is at a career-low 77 wRC+ and .281 wOBA. Matsui — playing in a reserve/pinch-hitting role for the first time in his career — has a disastrous 18 wRC+ and .195 wOBA. But both of these players have unusually low BABIPs and it is hard to know for certain if there has been a change in true talent levels or if this is random variation coupled with only mild aging.

In his reaction piece to the Ichiro trade, Eric Seidman rightly observed that Ichiro’s numbers should improve as he transitions from what has become an offensive deadzone in Safeco Park to the lefty-friendly grounds of Yankee Stadium, but how much can we expect his BABIP to improve? And what can the Rays expect from a 38-year-old Matsui, who may be needed more than ever with Luke Scott back on the DL?

Recent history suggests that both players are having abnormally bad BABIP, and they should improve if given consistent playing time through the rest of the season. But whether teams want to — or should — take that risk is another matter.
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