In last night's game recap, I made mention of Brian McCann's reverse platoon split this season and how he's hit left-handed pitching incredibly well while being downright awful against righties. It wasn't an exaggeration. After last night's game, McCann owns a .301/.345/.544 tripleslash in 103 PA against southpaws, good for a .388 wOBA and 147 wRC+. In 275 PA against righties, his slash line is .211/.270/.327 (.268/64).
That's an astonishingly wide OPS gap. Almost 300 points. It's even more astonishing when you consider that McCann's career OPS against righties is .834 compared to .755 against lefties, and his career batting average is 15 points higher against righties. This isn't a case of big variations from year to year either. Go back through each one of his Major League seasons and you won't find a single instance of McCann's OPS being better against LHP than RHP before this season. Since 2005, the formula has been that McCann hits for better average, better power, walks more, and strikes out less against righties.
That BB and K rate trends have held this year, which makes the dramatic shift in L/R split even more baffling. It's not like McCann is dinking and dunking his way to bunch of Ichiro-esque bloop singles against southpaws. His 27.4% LD rate against them is almost 6 points higher than his LD rate against righties (21.8%). Compare his season-long spray charts and there really isn't much difference between his BIP distribution against either-handed pitchers:
Same high concentration of pulled GB outs, same relatively even distribution of balls hit into the outfield, same HR pull power into right. There's nothing there to suggest that McCann is doing anything different mechanically or in his approach to lead to such drastically better results against left-handed pitching. So what are we supposed to attribute this change to?
When it comes to home runs, it may be as simple as good BIP luck. While McCann's FB rate against righties is almost 10% higher than against lefties, he has a 19.4% HR/FB rate against lefties. When he gets something in his kitchen that he can handle from them, he's cashing in big much more frequently. It's also worth pointing out that his BABIP overall against lefties is over 100 points higher than against righties (.321 to .219), so some better luck against lefties and worse against righties could both be combining here to arbitrarily expand that production gap.
I'd like to chalk some of that up to the shift, but from what I've seen in the games I've watched, there hasn't been a big change in how often opposing teams shift against him depending on what hand the pitcher is using to throw the ball. McCann has consistently been among the most shifted against players in MLB from day 1 this year, so to suggest that teams aren't employing the shift as much when their pitcher is a lefty seems overly simplistic.
McCann has been a huge disappointment at the plate this season, to the degree that his contract doesn't look as good as it did back in November. This severe reverse platoon split is among the most puzzling contributing factors to his decrease in production and I honestly can't offer up an explanation, so if anybody has seen something I haven't, I'd love to get your take. Maybe eliminating the toe tap made it easier for him to time pitches against lefties? I don't know. I got nothing.
P.S.- Commenter Bill actually pointed this out to me in my post on ways to improve the offense back on July 1st. I knew the idea came from somewhere and writing about him crushing lefties this season last night jostled my memory on it. Good on ya, Bill.