Looking for the perfect compby Chris Jaffe
July 16, 2007
The news that the White Sox had successfully re-signed their 28-year-old ace pitcher Mark Buehrle, who has taken the ball regularly over the last six years, to a contract extension for the next four seasons worth $56 million has put the sabermetric blogosphere all atwitter. And let's face it gang, no one quite puts the twit in atwitter like us. After all, as long as you're going to look at baseball numbers, why not try to evaluate a big contract signing? While Dan Szymborski, Chris Dial, and the rank and file denizens over at Baseball Think Factory have hailed this move, Mitchel Lichtman over at his blog and David Gassko right here at THT have sounded dire warnings.
Looking for the Lahman comp
The crux of this disagreement centers on how likely Buehrle is to remain healthy. One side thinks that since he's been durable, he'll remain dependably so. The other side bases its opinion on a study. Lichtman surveyed the Lahman database to see what happens to pitchers who, like Buehrle, toss over 200 innings a year without fail from ages 22 to 27. There are only 37 such individuals in all baseball history; of those only 32 pitched as many innings at age 28 as Buehrle already has. The results of that bunch are bleak enough to give anyone pause. They aged terribly, losing half their innings and seeing their ERAs rise. Yowsa. Clearly, that's a sign Kenny Williams may have made a bad mistake, right?
Well, maybe not. See, there's this bug in that study. The trick is that it's looking at all of baseball history. That might sound like a good thing, but it really isn't. If it was just liveballers that would be one thing. Or even if it was just 20th century pitchers it might not be that bad, but it's all of baseball history. I've looked this up before, and deadball era pitchers aged much worse than liveball guys. Men who threw in the olden pitchers' box days aged the worst of all, peaking at age 23. They're as good at age 32 as a modern pitcher is at age 37.
Unfortunately, it turns out most of the guys in that study were the long deceased. Only a third were liveballers with the remainder fairly evenly divided between deadballers and pre-1893-that's-hardly-even-pitching guys. I mean, are Charlie Buffinton and Jim McCormick really good comps for Mark Buehrle?
Also, the South Side southpaw had 100+ fewer innings pitched than all but two men in the study. Meanwhile two guys averaged over 500—yes 500—innings per season. While Buhrle hasn't cracked 250 IP in a season, about half of these peers averaged over 300 innings a season. Aw man, that can't possibly be right. You want him to be toward the middle of comparable players. I don't mean to go off on Lichtman or Gassko, because God knows they know more about math than I ever will, and do more good research by 9 a.m. than most people do all day, but there's gotta be a better way.
Looking for the perfect comp
You want to find good comps for Buehrle? Figure out what his main traits are, find guys with similar characteristics, and see how they aged. And only look at guys since WWII in order to avoid the problem of how pitchers aged differently way back when.
Buehrle has a few prominent qualities. First, of course, is that he's durable. I still want to take that into account. Second, he's a fantastic control artist. He walks barely two men per nine innings. Seymour Siwoff gives things away for free more often than that. Third, he doesn't strike many out. He's averages over five whiffs per nine innings, but way under six. That's especially crucial because as Bill James once noted, a pitcher's K-rate tells us a lot about how he'll age.
Here's the plan: go to B-ref's Play Index and look for guys who walk fewer than 2.5 batters per nine innings and strike out 6.0 or fewer from ages 22-27. No, check that last part. Let's make it ages 22-28. He's been having a fantastic year—it may end up being his best yet, and is a very good bet to throw 200 innings again. Maybe that's jumping the gun, but OK. Assuming Buehrle stays healthy, he should end up with 1,600 IP in those years. So I'll look at guys with 1,800-1,400 innings under their belts. There are 14 pitchers, including Buehrle who have done this since 1945. So, how'd they age?
Age IP WinShrs 22 183.4 10.5 23 232 15.1 24 230.2 14.5 25 234.2 14.2 26 226 13.2 27 235.9 14 28 204.5 9.4 29 180 9.8 30 151.3 8.3 31 137.9 7.9 32 146.5 9.5
Looks bad, doesn't it? But I've always felt that the work really only begins when you've got the numbers. Now you've got to figure out what the heck they mean. You see, this general trend didn't hold true for all pitchers in this group. In fact, they fell into two very clear yet separate aging patterns after age 28. Examining those patterns and determining how Buehrle relates to them will tell us how Buehrle is likely to age from here on out. Some of them aged pretty well, and others completely collapsed. There was no middle class.
Win Shares, Ages 29-32 Bob Friend 74 Claude Osteen 73 Milt Pappas 55 Jim Kaat 53 Dennis Eckersley 52 Brad Radke 47 Rick Wise 45 Bill Gullickson 21 Bill Monbouquette 14 Ralph Terry 13 Dick Ellsworth 10 Larry Sorenson 4 Ross Grimsley 1
See where Bill Gullickson is? Well, he missed his age 29 and 30 seasons with injury. And he's still ahead of a handful. And he's not even halfway to the guy immediately ahead of him, though. That's the break between the haves and the have-nots. The good news for Buehrle is many of the have-nots were already clearly on their way out before their age-29 season. Sorenson peaked at age 22. Terry and Ellsworth were on fumes. Meanwhile, Buehrle's on pace to rack up 22 more win shares this season. And others weren't nearly as good as he was. Gullickson was still a-chooglin' just fine at age 28. But going by win shares, his peak season would only be Buehrle's fifth- or sixth-best.
There's even better news for Sox fans. The haves, with only one exception, all went through a strange little blip in their late 20s. Just like Buehrle did last year, they had one long season where it looked like their days were numbered. Then they recovered, just like the man of the hour has in 2007.
In 1959, at age 28, right after a 22-win season, Bob Friend fell apart. He barely struck out 100 with his worst ERA in five years while losing 19. He came back next year to help get the Pirates a flag that flies forever.
Also at age 28, southpaw Claude Osteen had his ERA rise and his strikeouts dip down dangerously low. He still started 36 games, but for a man who had been selected to the previous year's All-Star Game, it was a letdown. Next year he won 20 games and kept doing fine after that.
Milt Pappas flopped at age 27. He'd played in the All-Star game the year before and was thought highly enough of to be traded for Frank Robinson. While Robinson won the triple crown in Baltimore, Pappas had his ERA skyrocket from 2.60 to 4.29. He shaved a full point off the next year and settled into a pitcher who was good though never great.
Dennis Eckersley was an all-star at age 28, and then became maybe baseball's worst starting pitcher at age 29. Then he helped get the Cubs in the playoffs at age 30. After a few more solid years as a starter, he made his historic move to the bullpen.
Brad Radke missed time with injury at age 29. He recovered and went back to being Brad Radke.
Nearly the same thing happened to Rick Wise at age 28, except that he lost a little when he came back. He was good for a few years, but never as good.
It's uncanny. They all slipped a rod at about the same point, got it adjusted, and went back on cruise control. Buehrle's done a nice job sticking to that part of the owner's manual. It's like you're not allowed to be a good veteran soft tosser unless you have that late 20s hiccup. Must be caused by some sort of ill side effects from the initiation rituals into the Secret Society of Crafty Soft Tossers. The bottom half of the list also had bad seasons in their mid-to-late 20s, but for them the good seasons were the ones that stand out. That ain't Buehrle.
The only exception is Jim Kaat. Even there, something's going on. He didn't lose one year, but a few years. In late 1967, in that historic pennant race, the Twins tried to win it on Kaat's arm, having him throw an ungodly 65 innings in September. His arm blew out in his last start (in Boston with the pennant on the line no less). The next couple of years, he wasn't quite as good. He recovered though, and arguably was at his best in the early 1970s. I doubt Ozzie Guillen will have Buehrle toss 50 innings this September.
So, the haves earned between 45 and 74 win shares in the upcoming years. Should we expect that from Buehrle? Perhaps, but that might be a bit low. You see, from ages 22-26, Buehrle was a much better pitcher than any of those guys. He earned 87 win shares; only Eck was within a dozen of that. In fact, through age 28, he's already ahead of any of them, despite his terrible time last year and this season only halfway completed. He may not do as good as Friend or Osteen because those guys tossed tons of innings as they got older. He might though, and he should end up closer to them than to Pappas or Kaat.
The only danger is that his K-rate, compared to league average, is bad even for this group. However, Buehrle's K-rate has declined very little so far. In fact, his 2007 rate is even better than his career rate. While it's true Bill James showed that K-rates are the best indicator of aging among young pitchers, one mustn't forget the exceptions. He noted that the rare pitchers who survived for a while despite low K-rates as young'uns all followed a similar pattern. They were left-handed, didn't walk anyone and were smart on the mound. Guys like Jimmy Key. And Mark Buehrle. I don't know if I'd want one of them in their mid-30s on my team, but Buehrle's only signed through age 32. Key was fantastic in his early 30s.
Predicting pitchers is less scientific an enterprise than alchemy, but I like this signing a whole heckuva lot.
History instructor by day, statnerd by night, Chris Jaffe leads one of the most exciting double lives imaginable; with the exception of every other double life possible to imagine. Despite his lack of comic-book-hero-worthiness, Chris enjoys farting around with this stuff. His new book, Evaluating Baseball's Managers is available for order. Chris welcomes responses to his articles via e-mail. Oh, and now he's on twitter.