Buzzing on Yahoo Sports:

Pitching by the Numbers: Half-baked notion

Michael Salfino
Yahoo Sports

We like stories and second-half splits tell us one: pitchers are good early in the year but tire late. They fade.

Give me last year's trailers in ERA and WHIP during the second half and I will certainly find examples that seem to support this theory. If you are so inclined, you will bet against them. Except that when you look at three-year splits, you find what you'd expect to find if second-half (or post-All Star) splits meant nothing – the bad second-half pitchers are mostly the bad overall pitchers and vice versa.

Some people even bet that pitchers who improved last year in the second half will improve this year, too. I'm not sure what the story even is there. Okay, they don't tire. But how can they get better as the season wears on?

Let's illustrate with leaders and trailers, post-All-Star break from 2009-2011 (minimum 200 second-half innings pitched). We'll start with leaders first, even though, again, what's the theory here even? I'm not sure. If you are a believer, please share in the comments or tweet me @MichaelSalfino.

Player W IP H BB K ERA WHIP
Clayton Kershaw 17 266 198 82 271 2.1 1.05
Felix Hernandez 22 315.67 267 87 279 2.54 1.12
Roy Halladay 26 309 289 47 275 2.59 1.09
Daniel Hudson 16 207 169 53 164 2.7 1.07
Chris Carpenter 24 327 295 74 246 2.72 1.13
Cliff Lee 22 299.67 277 35 283 2.85 1.04
Wandy Rodriguez 16 275.33 235 87 272 2.88 1.17
C.J. Wilson 16 217.33 179 85 229 2.9 1.21
Tim Lincecum 18 287 234 103 300 2.92 1.17
Hiroki Kuroda 16 244.67 215 50 204 2.98 1.08
Matt Cain 15 298 232 76 239 3.02 1.03
Ted Lilly 16 240.33 176 61 231 3.03 0.99
Justin Verlander 28 326.67 276 83 332 3.09 1.1
CC Sabathia 26 300 284 88 299 3.15 1.24
Cole Hamels 13 276.33 234 67 260 3.16 1.09
Zack Greinke 20 300.33 266 92 295 3.18 1.19
Tim Hudson 18 251.33 233 70 187 3.22 1.21
R.A. Dickey 9 212.33 202 50 116 3.31 1.19
Tommy Hanson 10 213.67 184 59 193 3.37 1.14
Roy Oswalt 15 221.33 213 47 175 3.38 1.17

Just a bunch of good pitchers. If second-half stats were not arbitrary endpoints, wouldn't you expect to see some pitchers who just got better in the second half? Maybe you say, "Well, no, because it doesn't make sense to get better as the season gets longer; only worse." More on that later. But for now, let's just dismiss the notion of better second-half splits for, say, last season having any predictive value.

And if you're still holding on to the notion that some pitchers on this list have pitched better in the second half than in the first, drop it. Look, if we were to stipulate that second-half performance is totally arbitrary and we merely have to look at the quality of the pitcher over the biggest relevant sample size to project him, we would still expect some variance. We certainly would not expect identical performance for first half during the period and second half, right?

Now on to the second-half trailers from 2009-11 (three years). Are they mostly the bad pitchers, period?

Player W IP H BB K ERA WHIP
Homer Bailey 16 233 241 79 200 4.25 1.37
Bud Norris 14 220 221 97 206 4.3 1.45
Trevor Cahill 17 262.67 271 97 154 4.35 1.4
Bruce Chen 15 225 236 76 147 4.4 1.39
Josh Beckett 16 255.33 262 65 246 4.41 1.28
Yovani Gallardo 18 234.33 226 81 262 4.42 1.31
Derek Holland 15 204.33 201 73 179 4.45 1.34
Roberto Hernandez 11 243 269 85 153 4.52 1.46
Carl Pavano 16 286.67 348 54 165 4.52 1.4
Tommy Hunter 19 251.33 273 59 132 4.62 1.32
Brett Cecil 13 210.33 228 71 140 4.62 1.42
James Shields 19 284.33 305 82 243 4.65 1.36
Mike Pelfrey 10 257.67 293 87 142 4.79 1.47
Derek Lowe 18 236 296 72 172 4.88 1.56
Jeff Niemann 17 228 229 72 192 4.89 1.32
Livan Hernandez 11 231 266 70 126 5.03 1.45
Ricky Nolasco 16 221 242 49 214 5.05 1.32
Jason Hammel 10 234.33 261 71 179 5.11 1.42
Paul Maholm 6 206 262 54 121 5.24 1.53
A.J. Burnett 11 249.33 282 107 231 5.56 1.56

Mostly, yes. Remember, Roberto Hernandez is Fausto Carmona. Also remember that Hammel was bad, period, until this year. Okay, Cahill is up about a run higher but he's a young pitcher and you can understand why guys prior to their mid-20s may not have fully developed man strength/stamina. For those who say, "Young pitchers present risk that they may fade as the season wears on," I can't argue. Gallardo also was 25 or under for the period. The Mets Jonathan Niese doesn't make the list, but same story with him (though this is his age 25 season, were we should stop worrying, generally). Shields and Beckett could definitely fit the story that they just get tired in the second half. But then why are their strikeout rates steady? Shields is off more than a run though. But last year, his second-half ERA was 3.35, lower than this first-half ERA for the period. Either way, I'm not going to hang an entire theory of projecting pitching performance on the thin reed of James Shields.

I provide this information because people want it and am doing so in a manner that I hope dissuades you from making transactions based on it. In fact, I encourage you to take advantage of your leaguemates who may overreact to the second-half meme. There are profits there to be made – with the possible caveat pricing more risk into younger, generally less physically developed hurlers.
View Comments (36)