Reverse Platoon Splits in the Royals Rotation

Mandatory Credit: John Rieger-USA TODAY Sports

Baseball dogma typically states that a right-handed pitcher should be able to get right-handed batters out more easily than left-handed batters, and that left-handed pitchers should be able to get left-handed batters out more easily than right-handed batters. Generally, that is true. In 2013, right-handed batters had a .691 OPS facing righties and a .741 OPS against lefties. For left-handed batters, lefties held them to a .645 OPS, while righties allowed a .738 OPS. It’s a similar story basically every year.

It makes sense, of course. It takes a bit more time to see the ball for a hitter on the same side of the plate as the pitcher’s throwing arm, and with less time to react, hitters will make weaker contact – or no contact – more frequently.

With the Royals rotation, however, that’s not always the case.

James Shields and Jason Vargas both have excellent changeups, and their ability to use those excellent changeups against opposite-side hitters allows them to neutralize the platoon advantage a hitter normally has, which has allowed both pitchers to show a reverse platoon split at some point in their career. Shields has allowed a .308 wOBA against lefties, and a .320 wOBA against righties in his 8 year career, and while the split isn’t extreme on the whole, it was much more evident in 2013. Last season, righties posted a .331 wOBA against Shields, while lefties could only muster a .276. That dropoff for left-handed batters is almost all due to Shields’ devastating changeup. For his career, left-handed hitters have a .211 average and .311 slugging percentage against the changeup, but last year those numbers fell to .202 and .254, respectively.

As for the southpaw, Vargas hasn’t always been able to limit opposite-handed hitters. Righties have a .327 wOBA against him and lefties have a .308 wOBA in his career. However, the reverse platoon split was certainly apparent last season. In 2013, righties were held to a .328 OBA while lefties teed off to the tune of a .345 OBA. As I mentioned a few weeks ago, Vargas’ changeup was much better last year than it had been in most of his career. Overall, righties have hit .199 with a .285 slugging percentage against the change, but in 2013 they hit just .180 with a .270 slugging percentage.

What helps Shields so much is his propensity to throw just about any pitch when a lefty is at the plate. Obviously the changeup is his bread and butter, but he still uses his other four pitches against opposite-side hitters. Against lefties in 2013, he used his changeup (31.4%), fourseam fastball (27.5%), cutter (16.1%), curveball (13.4%), and sinker (11.6%) often enough to keep the batters guessing. They know he relies on his changeup primarily, especially in two-strike counts, but they can’t sit on only the changeup, because Shields has the ability to mix it up.

Vargas, on the other hand, was primarily a two-pitch pitcher against righties in 2013. He did throw his curveball more frequently than in his career (11.4% in 2013, 5.9% in his career), but hitters still didn’t have much luck with the changeup. Again referencing the earlier article, Vargas was locating much better last season, and combined with more movement on the changeup, right-handed hitters just couldn’t make much solid contact.

So what does this mean for the Royals in 2014?

The Big Book of Baseball Managing usually tells managers to stack their lineup with opposite-side hitters, so they can take advantage of the normal platoon split. More and more teams are actually using platoons these days – not necessarily including the Royals, depending on how much you believe Dayton Moore’s comments – simply so offenses can try to gain every inch possible in the current run scoring landscape. In fact, two other AL Central teams will likely be using a platoon in their outfields. The Tigers will use Andy Dirks and Rajai Davis in left field, and the Indians appear to have a Ryan Raburn and David Murphy platoon in right. If both teams go strictly by The Book, the Royals could enjoy a bit of an advantage when Shields and Vargas take the mound against those two teams. Unfortunately, Brad Ausmus and Terry Francona are both pretty smart guys, so I’m guessing they would go along with what the data says and stick with same-side hitters when facing those two pitchers.

Even if those platoons aren’t used against Kansas City, they could still have some success. In a strange twist, one of the more heavily right-handed teams that Vargas could face is the Tigers. I’m not expecting the Royals’ 3rd or 4th best pitcher to shut down one of the top 2 or 3 lineups in the league, but he will likely be facing 6 or 7 right-handed hitters when the two teams meet, so perhaps that changeup could see quite a bit more action.

Shields and Vargas don’t mind seeing opposite-side hitters step to the plate against them. Both guys have changeups that can offset any platoon advantage, and if 2014 is anything like 2013, they’ll be able to flip that advantage into their favor.