Bronson Arroyo, Junkballer Extraordinaire

Two years ago, Bronson Arroyo was the very worst pitcher in Major League Baseball. Despite pitching in the DH-free National League, Arroyo led the Majors by allowing 46 home runs, 11 more than the next highest guy, who just happened to pitched in Texas, an offensive haven in the AL, where pitchers don’t get to face other pitchers. Arroyo gave up 15 more home runs than the next highest NL starter. By FanGraphs version of Wins Above Replacement, Arroyo was worth -1.4 wins, meaning the Reds would have been better had they just swapped him out for some dude from Triple-A.

At that point, Arroyo was a 34-year-old with a batting practice fastball who had just taken a run at the Major League record for home runs allowed in a season. He’d had a good reason as a big league pitcher, experiencing more success than anyone ever expected, but this looked like the end. Hitters had figured him out. Whatever magic he had used to get hitters out with his 87 mph heater had been used up.

Well, two years later, Arroyo is not only still around, he’s having one of his best seasons to date. The 36-year-old Arroyo has remade himself once again, and the pitcher the Cardinals will face on Sunday Night is not the same guy who was throwing BP back in 2011.

While he still throws the same basic assortment of pitches — four seam fastballl, two seam fastball, curveball, and change-up — as he always has, Arroyo’s variation on his arm angles and velocities have always made it seem like he’s throwing 10 different pitches. As he told David Laurila back in March:

I really don’t throw that many pitches, but I throw a lot of variations of my pitches. I throw a four-seam fastball, a two-seam fastball, a sinker, a curveball and a changeup. I cut the ball once in a blue moon.

[Pitch/FX] is reading a lot of different things, but what’s happening is that I’m taking my breaking ball and changing angles on it. I’m changing velocities on it. A lot of times, if I bring it more sweepy, they’re going to calculate it as a slider. If I throw it a little differently, they’re going to calculate it as a curveball. It’s the same pitch, I’m just changing arm angles.

I also might throw a four-seam fastball to start the game, at 80 mph. They might chalk that up as a changeup. There’s a lot of give and take in my game. I’m adding and subtracting a lot of velocities on different pitches that aren’t moving a ton. Sometimes if you throw an 80 mph little cutter, they might think it’s a changeup.

Other guys are a little more straightforward. It’s whap, whap, whap: Two-seamer, four-seamer, 93, 94, good breaking ball, and once in awhile, a changeup. That’s all there is. No variation. I could never get away with that. If I pitched like that, I’d get beat around the ballpark every night.

Back in 2011, Arroyo’s pitch mix looked like one giant cluster. He hit nearly every single velocity between 67 and 92, and all those pitches started to blend together. Here’s a PITCHF/x plot of every pitch Arroyo threw in 2011.

Arroyo2011

Most pitchers have distinct clusters. Their fastball is separate from their change-up, and their breaking ball often goes the opposite direction. Arroyo, though, through the kitchen sink at opposing hitters, and a lot of those pitches ended up over the fence.

This year, though, Arroyo has been a bit more conventional, giving some separation to the types of pitches he throws. Here’s that same plot, just for 2013.

Arroyo2013

The four seam fastball has been almost entirely replaced by his sinker, and he’s stopped throwing the flat breaking ball that doesn’t move that much, instead dropping his curve with more consistent movement while still varying the velocity. The result? He’s not hanging meatballs over the heart of the plate anymore.

According to his Brooks Baseball Pitcher Profile card, which shows the locations of each pitch as recorded by PITCHF/x, 8.6% of the pitches Arroyo threw in 2011 were middle-middle, right where hitters can barrel up the baseball. And it wasn’t just get-over fastballs in 3-0 counts when Arroyo knew the hitter wouldn’t swing either, these were low velocity breaking balls just floating down the middle of the strike zone. That year, 11.4% of his breaking balls were located in the most central part of the strike zone.

This year, that rate is down to 8.1%, and it’s made all the difference in the world. This year, he’s thrown 622 change-ups and curveballs, allowing just five home runs on those off-speed pitches, a rate of one HR every 124 pitches. In 2011, he allowed 25 home runs on 1,404 change-ups and curveballs, a rate of one HR ever 56 pitches.

Arroyo depends on deception and location to get batters out, and in the past, he was willing to experiment with so many different arm angles and velocities that some of them just ended up spinning in the middle of the plate. By streamlining the variations on his pitches, Arroyo has managed to eliminate most of the pitches that opposing hitters jumped all over. By becoming somewhat more predictable in what he throws, Arroyo has become harder to hit, because the extra variations on his velocity and movement were leading to hanging breaking balls in the heart of the plate.

Sometimes, less really is more. For Arroyo, scrapping the four-seam fastball and giving his breaking ball more consistent movement has helped him get his home run rate back under control, and now Arroyo again looks like a guy who very well might just pitch in his forties.




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Dave is the Managing Editor of FanGraphs.

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