Milwaukee Brewers v Houston Astros

Home and away splits are weird. Far too often, they are used as a weapon in an attempt to tear down players thought to be creations of their home environment.

In a fantasy perspective, they can be instructive when players change teams but, more often than not, they’re just noise. Matt Cain is held up as the poster boy for park factors, as his home/road results are often at odds.

Does it really matter to the Giants that Matt Cain is better at home than on the road? They signed him for what, seven years? He gets to call AT&T Park home for a long, long time, why wouldn’t they want him to pitch better there?

When looking at some splits for 2012, I came across the name of Bud Norris. As a pitcher for the Astros who already reached arbitration, Bud Norris is the subject of much trade speculation. Bud Norris, for whatever reason, sported the worst road numbers of any starter in baseball last year. His numbers were really bad. Shockingly bad. To wit:

I Split W L ERA GS IP H R ER HR BB IBB SO HBP WP BF WHIP SO/9 SO/BB
Home 4 1 1.71 11 73.2 54 16 14 5 17 0 82 3 2 293 0.964 10.0 4.82
Away 3 12 6.94 18 94.2 111 74 73 18 49 2 83 5 6 440 1.690 7.9 1.69
Provided by Baseball-Reference.com: View Original Table
Generated 2/21/2013.

The stark difference between his home and road numbers just…it just doesn’t add up. It was manner in which Norris compiled these ugly stats. He managed seven quality starts among his 18 road outings, the same as Adam Wainwright and one fewer than Roy Halladay and CC Sabathia. Both Wainwright and Sabathia were worse on the road, but not “ERA near 7.00″ worse. Looking at his road starts, there are a few true stinkers that ruin the entire split, none worse than an outing in Colorado where he gave up nine runs while recording a mere five outs.

Yet there lies Norris, surrendering a .389 wOBA on the road thanks to the 18 home runs. How is this possible? Will it continue? In a word, no.

As a pitcher who performs in a largely neutral ballpark (Minute Maid Park plays almost exactly neutral, favoring strikeouts and home runs slightly). That his home run per fly ball rate and BABIP are so much higher on the road (14.3% and .326 away compared to 7.8% and .263 home) is something we can certainly chalk up to randomness. His home numbers are sure to get worse just as his road numbers are sure to get better. That’s sort of how regression works!

His road average fly ball distance was essentially league average in 2012 (270 feet, 272 feet LA) and his well-hit average was, while bad, not bottom of the barrel bad. It ranked in the 25 percentile. There is nothing in any of the peripherals to suggest that Bud Norris won’t be his usual, league-average self on the road in 2013.

Pick a starter with exaggerated home/road splits and insert their name where you see Norris above. Barring any unforeseen environmental justification (i.e. Petco Park), pitchers are don’t perform differently when pitching on the road versus pitching at home.

For a pitcher like Norris, improved numbers on the road will only improve his final 2013 pitching line overall. Even if his home numbers worsen (as they almost certainly will), expect bigger things from Norris this season – though his switch to the American League might have something to say about that.