Matt Cain’s Struggles

You’ve probably noticed that Matt Cain is off to a bad start so far this year. He’s got a 6.49 ERA, and that includes his 6 innings of shutout ball against the Dodgers on Opening Day. In his last five starts — so, every start excluding Opening Day — he’s got a 7.85 ERA, a .859 OPS against, and he’s given up nine home runs. To put that in perspective, he gave up nine home runs the entire 2011 season. And he’s got a .265 BABIP, so it’s hard to say he’s had bad luck on that front, at least. So where have things gone wrong for Cain so far?

The easiest place to start is with those home runs. Cain’s given up 9 of them, and he’s currently sporting a HR/FB percentage of 19.1%. This, quite frankly, is unsustainable. The league average HR/FB percentage is usually around 10%, and Cain’s career rate is 7.1%. So we can expect his HR/FB percentage, and subsequently his HR rate, to go down over the course of the season.

The home runs are the main concern, because if you assume a league average HR/FB rate, instead of one almost double the league average, Cain’s been roughly the same pitcher he’s been for the last few years. He’s striking out more batters, but also walking more batters, than he has in the recent past, but for the most part he’s the same guy. The pitching statistic xFIP, which measures only a pitcher’s walks, strikeouts, and home runs allowed, and also assumes a league average HR/FB percentage, has Cain at just slightly better than his career average and slightly worse than the last two years. SIERA, a statistic developed by Baseball Prospectus that includes a lot more variables but measures roughly the same thing, agrees – Cain’s pitching about the same level he’s always pitches, maybe slightly worse, but nothing to get too concerned about.

But anybody who’s watched Cain’s recent starts has wondered if his traditional stuff has been there to start the year. I know I have, so I decided to take a look at the Pitch F/X data. According to the data, um, he’s kinda got his stuff? It’s just different. I’ll explain.

Cain has four main pitches in his arsenal: fastball, slider, curveball, changeup. He uses his fastball between 45-50% of the time, his slider around 20%, and his curveball and his changeup each around 15% of the time. I compared this April’s data to both his full-season numbers last year as well as the data from April only. The reason for this is because while doing my analysis I noticed that Cain has a tendency to increase his velocity over the course of the year.

His fastball’s been mostly par for the course. So far this year he’s throwing it 51% of the time with an average velocity of 91.35 mph. Last April, he threw it 49% of the time with an average velocity of 91.33 mph. The difference so far between this year’s fastball and last year’s is that he’s getting a different break on it. This year’s fastball breaks less downward – awkward wording I know but “breaks more upward” sounded worse – and more inside to a RHB. The pitch has been less effective so far this year than in year’s past, and the loss of some downward break could have something to do with it – the swing-through percentage on his fastball this year is about half his career rate.

His slider has been one of his best pitches historically, and he’s using it more than ever this year — 23% of the time. The slider he’s throwing this year is clearly different from the one he threw last year. In the past, his slider has had what’s called a two-plane break; that is, it breaks downward and also away from righties. But this year’s slider has almost no horizontal break at all, and instead has a more pronounced downward break. He appears to be releasing the pitch slightly lower than he did last year as well, which could have something to do with the difference in break. Another thing that’s curious is that the spin rate on his slider – the average number of times the pitch spins on it’s way to the plate – is 8.6% lower than it was last year, and 5.0% lower than it was last April. What does this mean? I don’t really know. It could mean lower arm speed – less torque on the ball means less spin, but then wouldn’t velocity be affected as well? It also almost certainly affects the break of the pitch. Less spin means the forces the air puts on the baseball are reduced.

His changeup is another pitch that’s about the same as last year. Cain’s changeup is unusual in the fact that it’s only about 6 mph slower than his fastball. Conventional wisdom holds that there should be about a 10 mph difference between a pitcher’s fastball and his changeup in order to successfully keep hitters off balance. Despite this, Cain’s changeup has been an effective change-of-pace pitch in recent years, and the raw data on his changeups this year is largely in line with that of last year. The velocity, break, and spin rate of the pitch is all roughly the same. Nothing to see here.

His curveball is another story. Historically, Cain curveball has been his worst pitch, if you believe Fangraphs’ pitch values (which the jury’s out on, but I’m running with it). This year, however, the pitch has been worse than ever, and you don’t need an advance statistic to see it. The pitch is breaking about two inches less vertically and one inch less horizontally, and the spin rate this year is almost 35% less than it was in 2012. Like his slider, his release point on his curveball appears to be about 4 inches lower than it was last year. Is this a coincidence? It could be. But it also could indicate a subtle change in mechanics that could be to blame for Cain’s poor start – and could indicate that the poor results he’s seen so far this year won’t change until he gets back, mechanically, to where he was last year.

Cain’s struggled in 2013, there’s no doubt about it. The easy explanation is that he’s given up a lot of homers – way more than is normal for him or sustainable over the long term. Remember, we’re talking about a grand total of 34 2/3 innings here. But there are a few indicators if you take a deep look at the raw data that indicates that some things are a bit different about this year’s Matt Cain as compared to last year’s. Is that a bad thing? Not necessarily. It’s definitely something to keep an eye on, though.

Cain’s next scheduled start is Sunday, Cinco de Mayo, against the Dodgers and Hyun-jin Ryu. While you’re watching, keep an eye on his breaking pitches. They’ve been Cain’s torment thus far this season, but with a few adjustments he’ll be back to the guy we’re used to watching.


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