The Riddle of Zack Greinke

Zack Greinke is the new Manny Parra, in that he's the Brewer pitcher I spend most of my time trying to figure out. With Manny healthy and back on the roster for the 2012 season, it's only a matter of time before we start rehashing the old discussions about his pitch selection and overall effectiveness. There will be plenty of time for that in-season. So to get warmed up I'm going to get right back on the horse and try to figure out what the heck happened with Zack Greinke in 2011, and hope that leads toward some kind of conclusion about what to expect this season.

Greinke started his time with the Brewers with some mind-bending results. He was doing just about everything right in his first starts, in terms of what he can control-- he was striking out a ton of batters and walking very few batters. His strikeout to walk rate was downright historic. He just was not getting results. Part of the problem had much to do with something he does have more control over: too many home run balls. But the rest of the picture didn't add up, because there was really no historical precedent for something this extraordinary, a 11 K: 2 BB ratio and an ERA that wouldn't get under 5 for a frustratingly long time.

Some deserved blame was placed on the defense, but an anamoly like this couldn't be the fault of the defense alone, which was actually just below average and not as bad as it seemed at times. There were other theories about Greinke trying too hard to avoid walks and throwing too many hittable pitches at times when he should have given in and thrown something out of the zone. There was another idea that this was just some horribly bad luck combined with a few poorly timed pitches and that things would even out over the course of the year.

In truth a combination of these ideas was probably the right answer to the question, "Why was Zack Greinke struggling?". As an analyst might have expected, Greinke's outcomes started to even out over the course of the year. He finished with a 3.83 ERA, 2.98 FIP, and 2.56 xFIP (xFIP adjusts for "home run luck", changing actual home runs to a percentage of fly balls). The end result certainly looked much prettier, but other problems held back his debut Brewers season from being a big success. First, Greinke struggled to go deep into games; he went over 7 innings just twice all season and never reached 8. Secondly, he failed to make a dominant impression on the postseason. The Brewers were 2-1 in his starts, but he gave up 3 homers and 4 ER to the Diamondbacks in his start in the NLDS, then gave up 6 ER in 6 innings (including a home run) against the Cardinals, then gave up 5 runs (only 2 earned) and failed to strike out a batter in 5 2/3 innings in his second start of the NCLS.

The new pitch f/x player cards over at Brooks Baseball are the place I started to look. I wanted to compare some numbers from Greinke from his dominant 2009, subpar 2010, and 2011, which fell somewhere in between those two final seasons with the Royals.

Here's a couple of quick charts on things that I thought were interesting. First is boring, pitch selection. Key point here is that his pitch selection changed in 2010 when he was apparently saving his arm while playing for a team out of contention, then basically bounced right back in 2011 to a mix similar to the one he had in 2009. I combine Zack's 2 and 4 seam fastballs here, more about that in a bit.

Next is whiff rate. This is off Brooks Baseball data, they now have a really useful tool to sort player pitches by sabermetric outcomes. Whiff rate is a nice proxy for nastiness of a pitch, it's the percentage of time a batter swings at a pitch and misses. It's closely correlated to overall strikeout rate.

This one's a bit more interesting. I would expect overall swings and misses to go up with Greinke's move to the National League, and in fact he set a career high in that category, with 10.6% last season. Relatively, however, the slider and curveball actually dropped a bit, and the increase in swinging strike rate falls almost entirely on the fastball-changeup combination, judging strictly 2009 and 2011.

Now to touch on the strangest part of Zack's 2011 season, and why I have so much optimism for him in 2012. Greinke set a career high in ground ball rate last season. He drew 40% ground balls in his phenomenal '09 season, upped that number to 46% in 2010 when it looks like he experimented much more with a 2-seam sinker, and then upped it again to 47.7 in 2011 while relying much more on the 4-seamer than he had in 2010. Greinke had a strangely high 22% line drive rate, something that we likely won't see again. 13.6% of fly balls against him left the park, a very high number. It was 4.5% in 2009, and that's something that can account for the difference between one of the great pitching seasons of all time and just a solid campaign.

Zack Greinke isn't the same pitcher he was in 2009, but he hasn't remade himself either. He uses the same general mix of pitches, with about the same levels of nastiness, but he's produced some different results. If he keeps maintaining his ability to induce ground balls, the infield defense will hopefully be improved enough to take advantage. And if that fly ball luck starts to even out, we could be looking at another stellar season from Grienke. I don't think it's going to be 2009 good- only a few pitchers in MLB history have had a better year than that one. But I'd put down money on him having some jaw-dropping numbers this year. The Brewers didn't get some Greinke 2.0 who rebooted after his 9 WAR season in '09, this is the same guy, and he's capable of doing it again.