At What Point Is the Sample Conclusive?

Egghead stat geeks like to make sport of the blatherrati for talking about who is a clutch performer and who chokes in the playoffs. In the broad sense, the evidence debunks the view that someone who performs a particular way in one or two series or one or two playoff seasons is "a great post-season player" or "can't handle the post-season."

Barry Bonds was always a good example of this. The greatest player I've ever seen, he struggled in his first few playoff series with the Pirates and Giants, managing just one home run in 27 games and a .310 OBP. 

He was labeled a choker who couldn't handle the big games.

Then in 2002 and 2003, he blasted eight home runs in 21 games, and got aboard at a .576 pace while leading his team to the World Series in '02. In that losing World Series effort against Anaheim, he hit .471/.700/1.294 for an otherworldly 1.994 OPS.

So much for choking.

Which brings us to Clayton Kershaw. After 10 seasons he has a 144-64, 2.36 career mark with seven seasons (I'm including 2017) finishing in the top 5 of Cy Young voting. 

He is without a doubt and by a wide margin, the greatest pitcher of this generation.

But he's stunk in the playoffs, and he's now played seven years of them. At what point is it fair to call him a regular season pitcher?

In 11 playoff series, Kershaw has a 5-7, 4.57 record. He's allowed 15 bombs in 100 innings, about what the league does against him in 220 regular season innings. His K/BB ratio is worse, his WHIP is worse; in short, he's not the same guy. And that's been true in almost every series in which he's pitched.

During the regular season, Clayton Kershaw is unhittable. He's Pedro Martinez. 

In the playoffs, he's a guy. He's Bud Norris, Bruce Chen, Randy Wolf.  

He's not just not Clayton Kershaw. He's leave-off-the-playoff-roster guy.

Is it possible that Kershaw just isn't very good in the playoffs? Maybe the stress gets to him. Maybe the way post-season games mess with normal rhythms of pitching unravel him. Maybe he hates cold weather, though there isn't much of that in Southern California (or Phoenix, their previous foe).

I don't know whether Kershaw isn't "clutch" or "chokes" or whether he doesn't perform as well for some other reasons. But at this point the evidence makes it pretty clear, he's not the same guy in the post-season.

Jumping Off The Lidge

Cory Wade, a second-year reliever for the Dodgers, is 0-3 with a 5.12 RA so far this year. In 19 innings he's issued 10 free passes and surrendered 21 hits. Knowing that, you wouldn't want him coming into a close game in the eighth inning if you were a Dodger fan.

Until you discover that Wade had one bad outing in which he got shelled for seven runs. Other than that, Wade's held the opposition to four runs in 18 innings, for an RA of 2.00. Maybe you do want him pitching in the eighth inning of a close game.

Thus have I illustrated the problem with small sample size, which plagues analysis of relief pitchers even from one year to the next, and which brings us to the sad, sad tale of Phillies closer Brad Lidge.

Lidge was lights out for the World Champs last year, recording 41 saves in 41 chances and limiting opponents to a 2.21 RA. (Sometimes we hear his record described as "perfect," which we all understand to be hyperbole. On several occasions, Lidge entered games with three-run cushions and made it interesting, but nonetheless got the save.) This year he's turned into Brad "Jump Off The" Lidge, blowing six of 19 save opportunities and posting a 7.20 ERA. (His RA is a bit higher, but I imposed the mercy rule and declined to calculate it.)

It seems that something dramatic has happened, either to Lidge or to batters facing him, but one thing we know it's not is fatigue. He threw all of 69 innings last year and has racked up just 25 in '09. Something not particularly dramatic has occurred too. Think of Lidge as a starter and ignore the calendar for a moment. Then you have a guy who shut down the opposition for his first 10 or so starts before getting hammered in his next four or five. Suddenly the progression of these two seasons doesn't appear so odd. Pitchers go through hot streaks and slumps just as hitters do, make adjustments, gain or lose confidence, etc. The small number of batters faced by a closer in one baseball season just isn't enough to evaluate with much degree of confidence.

This is the reason that relievers are notoriously unpredictable from one year to the next, and why guys who are consistently spectacular, like Mariano Rivera and Trevor Hoffman, are so amazing. It should also serve as a cautionary tale before we anoint some new closer with superlatives. Are you listening Heath Bell?

The former Met has been a wonderful surprise for San Diego so far this year. Striking out more than a batter an inning with a WHIP under 1.00 has led to 16 saves and a 1.61 RA, great even in Petco. But it's all been in 21 innings -- three quality starts. It's possible that no batter has yet seen Bell more than once this season. We don't draw conclusions about starters after facing 86 batters and we should be careful about it with relievers.

The larger point, of course, is that extrapolating from a fraction of a season is a fool's errand. That's true to start a season, during the stretch run, in the playoffs, after an injury, or around the discovery of steroid use. The vagaries of luck and human psychology can transform a player's performance during any short stretch into something historic. But it doesn't necessarily mean anything. Just ask Cory Wade.
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