Bill Petti published the first two parts of a series on pitcher aging. Bill’s first article focused on pitchers, in general, and the second was on the difference between starters and relievers. For the third installment, I’ll look at aging patterns for pitchers who maintain a relatively constant velocity from year-to-year.

From the previous articles, the average pitcher loses about 4 mph from their fastball from ages 21 to 38. In essence, most pitchers’ stats degrade as their fastball speed drops. Using the same methodology, I wanted to know how pitchers age when they don’t lose velocity on their pitches.

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After suffering through an abysmal 2011 season, White Sox designated hitter Adam Dunn is off to a fantastic start this year.

Last season, the 31-year-old Dunn put up a career-low .266 weighted on-base average (wOBA), or 59 wRC+, in nearly 500 plate appearances. His on-base percentage — which normally was a strength for the slugger — was .292, or 62 points below his previous career low when he was 23. Most disturbing was the sudden disappearance of his power. Dunn has always been a high-strikeout, high-walk, high-slugging player. But last year, Dunn posted an isolated power of only .118. To put that into perspective, consider this: Dunn’s ISO was only two points higher than Nyjer Morgan’s (.116). Dunn also saw his HR/FB ratio drop to 9.6% in a hitter- and home-run-friendly park. His previous career-low was 17.8%, all the way back in 2002.

But now? Well, we’re seeing the old Adam Dunn. Through May 7, he has managed a .394 wOBA, which is fueled by a .364 OBP, .321 ISO and a 28.1% HR/FB. And both the ISO and HR/FB numbers are better than his career highs. The obvious question is whether these numbers are sustainable. Given how quickly outcomes like BB% and HR/FB stabilize, there’s a good chance that Dunn’s end-of-season numbers could be similar to what they are today. The question I have is what is Dunn doing differently? To get a better handle on this, I took a look at Dunn’s performance on specific pitches in different locations.

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On Monday, Jeff Zimmerman and I launched our series of articles on pitcher aging. Readers should refer to introductory article, which includes general curves and a summary of the methodology. The general takeaway was that, as suspected, pitchers age differently than hitters. Generally, pitchers see their velocity peak in their early 20s and steadily decline by a full mile per hour by age 26. After that, velocity drops more sharply and continues a steep decline into a pitcher’s 30s.

Strikeout rates were tied to velocity, but not as closely after age 26. This indicates that those pitchers who survive into their late 20s and early 30s are less reliant on their velocity (and, most likely, their fastball) for strikeouts. A pitcher’s walk rate shows a some improvement through age 25 (due to starters), and then begins its decline.

In this article, I want to tease out some of the differences between starters and relievers.

Let’s quickly recap what the average aging curves look like for starters and relievers:

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As on-field performance data has evolved, baseball enthusiasts have been spoiled with more precise measures of player performance. One area in particular is pitcher velocity. Whether through Baseball Info Solutions (BIS) or PITCHf/x, writers and researchers can now add a critical variable into their analysis that wasn’t readily available a decade ago.

Many readers of FanGraphs and Beyond the Box Score have seen Jeff Zimmerman’s position player aging curves. After reviewing them, I started to pester Jeff to see if he considered similar curves for pitchers — specifically in the area of fastball velocity. I was curious about the general pattern of decline for fastball speed and how it impacts overall pitcher performance. Luckily, Jeff already had been thinking about this.

Today, Jeff and I are launching a multi-part series on pitcher aging curves, which is centered on fastball velocity. This introductory article will lay out the methodology we used and — of course — the initial baseline curves for all pitchers, as well as starters versus relievers.

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During Monday’s Baseball Today Podcast, Eric Karabell and Mark Simon were discussing a listener’s question regarding who has made the most outs per plate appearance in a single season. The idea here being you want to not only look at hitters with low on-base averages (OBA/OBP), but also include the extra outs generated by grounding into double plays*.

It is an interesting trivia question. And since I am pretty well jammed up this week working on multiple projects and deadlines I thought this would be a nice, quick topic to tackle.

To calculate this I looked at all players with >= 300 plate appearances in a season since 1950. I then calculated the outs they generated–((AB+BB+HBP+SF)-(H+BB+HBP))–which is really just reverse OBP, and added in the total number of double plays that they grounded into for the season (GDP). I then took this number and divided it by their plate appearances for the season to get their Total Outs Generated per PA.

Here are your top 10 and bottom 10 since 1950:

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Carl Crawford, Adam Dunn, and Jayson Werth signed large free agent contracts with new teams last offseason, and each were unequivocal disappointments in 2011 with their new club. This phenomenon is not limited to free agents. In recent memory, several highly touted prospects have been traded and not lived up to expectations with their new teams: Justin Smoak, Brett Wallace, and Kyle Drabek, to name a few.

Whenever a player changes teams and fails to live up to expectations, I find myself wondering, “Did his old team see this coming?” In these specific examples, we may never know, but we do know that teams have internal information which creates an advantage in personnel decisions. While this advantage may never completely go away, there is evidence to suggest that it’s starting to disappear.

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Fernando Rodney has three saves and a win so far this season. Fernando Rodney has gotten eight outs so far this season. As strange as it may first seem for a late-inning reliever to have four decisions with so few batters faced, it’s business as usual in Tampa Bay. Here’s a box score that is fairly typical for the Rays:

It certainly appears that the Rays are micro-managing their bullpen. Perhaps the aim is to gain the platoon advantage in as many situations as possible — teams do that all the time. But which ones are doing it most often?

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This past Tuesday on MLB Network’s Clubhouse Confidential, I predicted that Mets first basemen Ike Davis would be the breakout player in MLB this coming season. Yes, it was a bit of a homer pick, but I had solid reasoning to back it up. In his first 754 plate appearances in the big leagues, Davis put up an OBP of .355, a SLG of .457, and a wOBA of .352 all while playing in the pitcher-friendly Citi Field. That translates to a 121 wRC+, not bad considering only six other players 24 years old or younger have ever matched or exceeded that total over their first 800 plate appearances.

While watching Davis go 0-for-4 with two strike outs in yesterday’s opener I noticed something interesting: the Braves only threw Davis one fastball out of 18 total pitches. Not only that, but 41% of those pitches where thrown low and away, with Davis striking out twice on pitches in that area.

We can’t read too much into performance metrics in the early part of the season, especially after the first game, but the strategy executed by the Braves yesterday is consistent with the book on Ike, and may have provided a preview of what the young slugger will see throughout the year.

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Most readers understand that the phrase Three True Outcomes (TTO) refers to walks, strike outs and home runs. In an August 2000 article at Baseball Prospectus, Rany Jazayerli noted that these outcomes are “true” in the sense that they are largely independent of all things — outside that mano-a-mano moment between the batter and the pitcher:

Together, the Three True Outcomes distill the game to its essence, the battle of pitcher against hitter, free from the distractions of the defense, the distortion of foot speed or the corruption of managerial tactics like the bunt and his wicked brother, the hit-and-run.

None of the three true outcomes are significantly impacted by what happens outside the batters box*. Therefore, players with a higher percentage of plate appearances that end in TTOs have their fate largely decided at the plate. The poster child for the TTO? Rob Deer. His career TTO percentage ((HR+SO+BB)/(PA)) was 49.7%.

I thought it’d be interesting to look at how TTO players have evolved over time and what accounts for their successes and failures.

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Part two of a two-part series.

In Part I of this series, I dove into some Pitch F/X data to try and tease out how Adrian Gonzalez changed his approach after leaving San Diego in 2011. Overall, pitchers did not appear to adjust their approach to Gonzalez, evidenced by the fact that the distribution of pitches by location in 2011 was almost identical  to 2010. Gonzalez, however, did seem to alter his approach by altering what pitches he offered at, most notably swinging at more balls away and up in the zone. The change in his swing distribution combined with the change in his performance seemed consistent with the theory that the slugger was purposefully being more aggressive on pitches outside of the strike zone in an effort to take advantage of the Green Monster at Fenway Park. But to get a firmer handle on this we needed to split out Gonzalez’s data by home versus away.

That is the focus of this article.

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