Explaining Johnny Cueto's disastrous second half

The Giants signed Johnny Cueto yesterday to a lotta years/$Lotta deal, unless he decides in 2017 he'd prefer a less years/$Still Lotta deal. Either way, and discounting the possibility of some Orioles-like tomfoolery with his physical, he's a Giant, so we can turn our attention from asking "He makes HOW much?" to asking "In the second half, he was HOW bad?" It's a charmed life, caring about sports.

Here's a quick rundown of what happened to Cueto post-trade: he got fewer strikeouts, walked slightly fewer batters, gave up more hits, gave up more home runs, and gave up more runs. His BABIP shot up, his LOB% hit a career low (meaning that a greater percentage of his baserunners than ever came around to score – that's potassium benzoate-level bad), and his BAA was 54 points higher than it had ever been.

So how do we explain this? What did Cueto do differently after being traded from Cincinnati to Kansas City? Fangraphs' August Fagerstrom tried to figure out what had been wrong after Cueto's (quite good) second ALDS start in October, and after considering some other theories that had been bandied about (tipping pitches, bad chemistry with Sal Perez, bad luck), what he saw was Cueto not throwing hard enough.

From August 21 to October 4, a nine-start stretch in which Cueto posted a 6.49 ERA for the Royals, his average fastball velocity, the first time through the order, was 91. The second time through the order, it was 92. By his third time through, he’d ramped it up to his normal speed of 93, so it’s not like Cueto had lost the ability to throw 93, he just hadn’t shown the ability to do so in the early innings.

And to an extent, the numbers proved him right: with the Royals, Cueto's strikeouts and effectiveness (in terms of ERA) both improved going from the first three innings (1-3) to the next three (4-6), and (microsplits on microsplits alert) he continued improving his ERA in innings 7-9, though his strikeout rate was essentially unchanged. But if you look at the stats more closely, while Cueto didn't strike out as many guys, he also didn't walk as many, and he gave up fewer home runs. The biggest culprit in his poor performances in those innings was a ludicrous BABIP of .391, something unlikely to be sustainable over a long period of time, decreased fastball velocity or not.

And it should be noted that his fastball velocity did decrease, but not by that much; Brooks has the yearlong chart showing a slight decline in four-seam and two-seam velocity, though Cueto's cutter took a bigger hit:

But that's not really that big a drop; other than in June, his four-seamer was usually around 93.5 MPH, and in his two really bad months with Kansas City it averaged a tick under 93 MPH. So what about movement?

Again, you see a small difference, but not the catastrophic one that should have led to the stats Cueto put up. The vertical movement on his various fastballs doesn't correlate with any change in effectiveness, and while his slider and changeup lost a little downward action as the months went by, they weren't enough to change Cueto from Unstoppable Pitching God to J.A. Happ Wannabe.

But that was only vertical movement. What about horizontal movement? Surely there will be some magic bullet there that explains everything and makes you feel smarter for noticing it.

Aw, nuts.

The only remarkable thing there was the increased grouping of the four-seamer, two-seamer, and changeup as having the same amount of horizontal movement as the year went on. Could those factors have contributed to an increase in hittability? Sure. Does it explain anywhere near the results we saw? Probably not. Combined with the other tiny factors seen above, does that make it enough? Again, probably not.

No, it looks like this is mostly a fluky BABIP thing. Accounting for the slight dings in velocity and movement, accounting for Cueto not getting to face a pitcher anymore, and accounting for a drop in strikeout rate, it still looks like that .343 BABIP in Kansas City is the biggest factor. He's always been such a low-BABIP guy in his career, possibly because he's so good at getting into two-strike situations, that the massive and unprecedented rise there crushed him.

When you look at Cueto's batted ball profile, he did several things worse, but giving up line drives three percent more of the time than he had just doesn't explode a pitcher's numbers. He got into two-strike counts slightly less often with the Royals than he had with the Reds, marginalizing that two-strike BABIP advantage. He also gave up a microscopic increase in the percentage of balls hit hard. And there were, as mentioned before, small decreases in velocity and movement. But none of those are the silver bullet. They're just a bunch of silver bees, and they can't do much worse than deal out a few annoying stings.

In the end, Cueto did a lot of things slightly worse in Kansas City than he did in Cincinnati. But taken together, they really don't explain his decline there. While there was a significant decrease in his strikeout rate and a significant increase in his home run rate, the blame mostly falls on those capricious jerks, the BABIP Gods.

Johnny Cueto has never been a top strikeout guy, but he's also never been as bad at striking guys out as he was in Kansas City. His home run rate there was also a little higher than his career rate, and you'd have to imagine that that aspect of his game will only improve in San Francisco. There isn't a lot of reason to expect his bad fortune to continue with the Giants, and it just might have gotten them a better deal for Cueto than they would have otherwise found.