The second half travails of Adam Wainwright

There was a time, as recently as June of this year, where a 3-0 Cardinals lead in the first inning and Adam Wainwright on the mound would have led to a check of the box scores to see if the team would be picking up a game on the Brewers. With a mid-season ERA below 2.00, a 3 run lead for Wainwright seemed insurmountable in June (until, of course, the inevitable "save situation" in which we must use our closer no matter what, even if he's imitating Rod Beck), and Cardinals fans could settle in and watch the future All-Star starter carve up the opposing lineup for the next 7-8 innings.

Lately, as recently as last night as a matter of fact, that's not been the case. After posting a ridiculous 4.26 K/BB in the first half of 2014, Wainwright has regressed to a 1.76 K/BB rate in the second half while his ERA has ballooned by nearly 3 runs (1.83 to 4.70) and while his FIP and xFIP have shown smaller regressions, both are up nearly 1 run per 9 innings pitched since mid-July.

So what's going on? Should he be drinking his smoothie an inning earlier? Digging into the data over at brooksbaseball.com, I found a chart that seems to explain a lot of his struggles, all wrapped up in one tidy package:

The two charts above are the percentage of whiffs that Wainwright is getting from hitters in different areas of the strike zone. The top chart is Waino's stellar first half and the bottom chart is the second half struggles.

What immediately sticks out is how the second heat map is nearly inverted from the first one: During the first half, Wainwright was getting tons of swings and misses in the lower half of the strike zone, nearly a quarter of the pitches that he threw in the below the bottom half of the strike zone were getting swung through by opposing hitters.

Ignore for a moment the deep red at the top of the second half chart and look instead at the bottom of the heat map: Where did all those swings and misses from the first half go? Wainwright is pitching down in the zone just as much as he was earlier in the season, but he's not missing nearly as many bats. Swing rate on those pitches is about the same as it was before, so it's not like hitters are laying off of pitches below the lower half of the strike zone. Hitters aren't getting more hits on those pitches either.

So how is this hurting his overall performance?

By making Wainwright work a lot harder to put hitters away.

In the first half of the year, if he got ahead of hitters, Wainwright would just pound the lower, outer half of the plate with two seamers, sinkers, and his devastating curveball and since hitters were swinging through 25% of those pitches, that resulted in a lot of outs without the ball ever being put in play.  Lately, he's not getting those whiffs and that leads to him having to come into the strike zone more often (which has resulted in a higher ISO on balls in play) and an uptick in his overall walk rate as well given that he's getting fewer swinging strikes, resulting in more 2 and 3 ball counts.

So the natural question to ask is: What's causing hitters to make more contact, fair or foul, with those former "put-away" pitches?  Honestly, I have no earthly idea. I've spent a few hours looking at all kinds of splits  to see if I can figure it out and have come away stumped as to the change in hitter behavior. My conclusion is that it might just be a bit of a small sample size that will likely right itself -- Wainwright has been on the record with Goold discussing how uncomfortable he's felt on the mound the last month or so. Perhaps this will all go away when he's back to his old self.

Let's just hope that happens this September rather than next March.