Why is Brandon Belt striking out so much now?

Brandon Belt deservingly made the All-Star team for the first time this year, and after playing in the game, immediately went into a massive slump. In the 8-game road trip after the break, he went 2 for 33 with 4 walks. He’s recovered somewhat since then, but he built his first half success on a career low strikeout rate and a career high in power, and while the power has mostly come back, the strikeouts have continued to mount, to the point where his second half K% is 31.3%, which is very, very high. What’s going on with him?

Let’s start out by looking at how often he’s been swinging and missing as the season has progressed:

First off, you can see here the good things he’s done this year. Belt’s improved quite a bit from previous years on offspeed pitches (changeups and splitters, mostly), and at the beginning of the year, he was making a ton of contact on everything. But as 2016 has passed, he’s started to have more and more trouble hitting fastballs. At the beginning of the year, he was only swinging through a sixth of them, which is really good! Now he’s whiffing a third of the time, which is not as good. He should go back to doing the thing that’s good instead of continuing with the thing that’s pretty bad.

What about the pitches he’s chasing? If he’s going after balls that aren’t in the strike zone, then ... you know, that doesn’t really sound like Brandon Belt. He has a tendency to strike out looking on a pitch that misses the strike zone by an inch, and trudge back to the dugout being right. So what’s he doing with two strikes? Is that very convincing anecdotal evidence right?

Not really, no (Before the break, he was swinging at 32% of two strike pitches outside of the zone, and now he’s dropped it a bit to 29%), but one interesting thing is that he’s doing less swinging at pitches in the zone with two strikes than he did before. Belt’s taking more than twice as many pitches inside the strike zone with 2 strikes (16% of them now, as opposed to 7% before the break), which leads to strikeouts.

But enough about when Belt doesn’t swing. What happens when he does? Is there anything there that can explain the increase in strikeouts?

He’s swinging through way more pitches! And, sadly for the Hole In His Swing narrative, those swing throughs are all over the strike zone, and not confined to pitches up and in. Before the break, he was whiffing on 15% of 2-strike pitches in the zone, and since the break it’s been 24%.

When you look at what pitchers have been throwing Belt, you add a little more clarity. Here are two tables, sadly not side by side, as I don’t think they would be big enough to read:

Since the All-Star Break, Belt’s seen far, far fewer fastballs from lefties, and moderately fewer from righties. The only real exceptions to that are against righties, when Belt’s ahead in the count, and when there are two strikes. When he’s ahead in the count, he can look fastball and just plan to lay off anything else, which is probably why his exit velocity when he swings at fastballs hasn’t really changed this year. But when he’s at two strikes against righties, and he’s probably been seeing breaking stuff through the AB and keeping it in the back of his mind, that adjustment gets a little harder.

That seems to be the exploit that opposing pitchers have found. Now it’s time for Belt to adjust right back, sit offspeed stuff earlier in the count, maybe rotate his knuckles (shout out for the longtime fans!), and get back to being an All-Star.