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Zack Greinke: NL Starting Pitcher

Conclusions first: Those who drafted Zack Greinke didn’t do so to have him sitting on their bench for half of his starts. Those who have invested either the draft pick or the talent it would take in order to get him via trade, should be getting the full value out of him and starting him every time the Brewers give him the ball, because even when he’s not pitching well, he’s still seldom that far below average. His two worst starts of the season happen to have come on the road: His 3.2 IP, 8 ER effort in Chicago and his 2.1 IP, 7 ER shelling at the hands of the Diamondbacks were both aberrations even for his road struggles. While he hasn’t set the world alight in his other sojourns away from Milwaukee, he’s hardly pitched the Brewers out of those games.

Still…it’s unusual that Greinke has been so much worse on the road than he has been at Miller Park, right?

In reality, given the incredibly high bar he’s setting at home — 4-0 with a 0.79 WHIP, a 1.08 ERA, and an 11.2 K/9 in six starts — it would be far more remarkable for him to post a similar line on the road. After all, a full season at that WHIP would be the second best mark since 1980 behind Pedro Martinez’s incredible 2000 season. But while some decline on the road is to be expected, it’s the magnitude of the drop that is somewhat incredible. His line on the road — 3-2 with a 1.68 WHIP, a 4.96 ERA, and an 8.5 K/9 — would rank him near the bottom of the qualified starters in the league so far this year rather than up with the greats of the last three decades. So why has Greinke become the NL Central’s version of Dr. Jekyll and Mr. Hyde?

Greinke’s walk rate is almost identical at home and on the road, so the difference in his WHIP and ERA comes down primarily to hits. The nearly 200 point gulf in his home and road BABIP, .253 at home versus .425 on the road, goes a long way to explaining why he’s given up hits to 16 percent more hitters away from Miller Park than at it, but it’s a bit too much oversimplification to say that he’s simply been unlucky when the Brewers bat first. His line drive allowed rate is nearly 10 percent higher on the road than it is at home, and at 28 percent, it’s far above where one might expect it to be for an elite pitcher.

It would be convenient if Greinke’s poorer outings had a singular cause: a drop in velocity, a weird usage pattern, a complete abandonment of one pitch or another, but the correlations between each of those factors and his worst showings is weak at best. Digging into his poor performances yields precisely what one might expect: Tautologically, when Greinke isn’t sharp, he doesn’t pitch very well. While this isn’t exactly an earth-shattering revelation, it’s actually good news. Every pitcher has bad outings — though R.A. Dickey may look as though he’ll never have one again — and it’s less worrisome that Greinke simply got punished when he didn’t have his best stuff than something being systemically wrong with him.

It’s cherry picking to simply eliminate Greinke’s worst outings, but with that caveat out of the way, in this case it’s also instructive. Looking at his road starts without his April 12 start against the Cubs and his May 26 start in Arizona, Greinke’s away numbers look much more like his home figures. His WHIP falls to 1.35, his ERA drops to 2.29, and while his K/9 also slips down to 8.0, that’s a tradeoff most owners would make in a heartbeat. With that deviation instead of the chasm that lies between his actual home and road numbers, his exceedingly high line drive rate and by extension his hit rate explain most of the difference in results. He’s getting hit a little harder on the road, but not so much as to cause a great worry.

Returning to the beginning, owners should have always planned to play Greinke, even on the road. Now, however, they can play him with the confidence that there isn’t a singular cause that’s going to consistently derail him when he isn’t pitching in the good land. NB: His next start comes on the road against the White Sox; if they do him slight the way they did Clayton Kershaw, I’m not abandoning this conclusion. It’s a hitter’s park and they have a potent offense. I’d still start him, but the potential exists for another cringe-inducing effort.