Examining the Red Sox' problem against left-handed pitching

Generally speaking, the Red Sox have been an outstanding offensive team this year. While the pitching has been off and on, the lineup has been mostly consistent and has led the team to a 16-11 start. As of this writing (prior to Thursday night’s game), they are the second-best offense in the game by wRC+, coming in with a 116 mark that trails only the Cardinals. A big reason for this is the fact that they’ve faced a lot of right-handed pitchers relative to the rest of the league, and they’ve been tremendous against them. To wit, their 128 wRC+ with a righty on the mound is tops in the league. Unfortunately, they’ve been much, much worse against left-handed pitching.

Right now, the Red Sox lineup has a collective 64 wRC+ against lefties, worse than every team outside of the Phillies and Braves. If you haven’t been following the league as a whole, those are not two offenses you want to be in a group with. Now, there’s a decent chance that some of this is a small-sample size issue, even beyond how early in the season it is. As I said above, they’ve faced a ton of righties, which obviously means they’ve faced fewer southpaws than most teams. To be precise, only the Mets, Twins and Marlins have fewer plate appearances in this split. Boston’s offense has also suffered from a low batting average on balls in play against lefties, with their .262 mark coming in as the fourth lowest in baseball. However, we all know by this point that BABIP can’t simply be explained away by bad luck. To get to the bottom of these problems, I looked at the four biggest culprits to see whether or not there are any troubling signs.

Dustin Pedroia (-47 wRC+ vs. LHP)

We’ll start from the bottom of the team’s wRC+ leaderboard, because that was one of my two options and that’s the one I chose. Seeing Pedroia in a discussion of troubles against left-handed pitching is a bit jarring as he’s always had success against opposite-handed pitchers. The biggest culprit for his poor production has been an uncharacteristically high strikeout rate, with a 26.7 percent rate this season versus 9.5 percent over his career. However, his pitch breakdown on Brooks Baseball doesn’t show any major concerns. He is swinging and missing against changeups more, but it’s a small sample and some of that came against Jose Quintana, whose changeup has done that to many righties this year. As for his lack of power and general success on balls in play, there’s plenty of reason to believe he’ll turn it around. His line drive rate is near it’s normal range and he’s pulling the ball more. Furthermore, his exit velocity is actually up from last year. The one concern is that his ground ball rate is way up while his fly ball rate is way down, which is a bad sign for his power production. All in all, this screams small-sample noise, with the only slight concern could be depressed power production.

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Travis Shaw (-46 wRC+)

Coming in just ahead of Pedroia is Shaw, who is an interesting name for this discussion. John Farrell caught some flack this year after pinch hitting for Shaw against lefties after the third baseman flashed reverse splits in 2015. Those reverse splits were suspect last year, and he’s not backing them up in 2016. His strikeouts are up to 29 percent from 24 percent last year. His Brooks Baseball page isn’t as forgiving as Pedroia’s, either, as he’s struggling against velocity coming from the left side. Specifically, his whiff rate is up significantly against fastballs and cutters. He’s also suffered from a BABIP regression, falling to .125 from last year’s .368 mark. Now, obviously this is an overcorrection, but there are troubling signs as well. The power is down, which could be a sign of hard contact. The deeper numbers back that up, as he’s hitting a ton of pop ups and ground balls while no longer pulling the ball as much. His soft hit percentage on Fangraphs is way down, as is his exit velocity. He’s not going to be this bad against lefties, but I’m confident in saying those reverse splits last year were a mirage.

Mookie Betts (-32 wRC+)

If you were surprised by Pedroia on this list, you may have had a cardiac episode seeing Betts’ name. Luckily, you won’t be too shocked by the deeper numbers. Like the others on the list, his strikeouts are way up. It makes sense, of course, for those in the midst of small-sample struggles to suffer from a strikeout uptick. The main culprit has been offspeed pitches, but he’s been attacked almost exclusively with fastballs. He’s been fine against that velocity, at least in terms of contact rate. His fly balls are up, which is good for his eventual power. The flip side, however, is that he’s not pulling the ball as much. A more balanced spray chart will help his BABIP, but hurt that power. Finally, looking again at the exit velocity, he went from a good number last year to a great number this year. All of this points to an eventual bounce-back from Betts.

Hanley Ramirez (60 wRC+)

Ramirez is leaps and bounds ahead of the other three names on this list, but he was the most concerning to me before I even did the deeper research. I was already worried about his offense after last season and his slow start this year, and seeing that he’s struggling against opposite-handed pitching doesn’t make me feel much better. The good news is that there is no major change in his performance against specific pitch types. The bad news is how he’s hitting the ball. While it’s coming off his bat harder, which is great, it’s heading into play on the ground. This has been a problem for Ramirez over the last couple of years, and is the biggest reason we haven’t seen the power we expect from him. On top of that, he’s hitting the ball the other way almost half the time against lefties. I would expect more hits than he’s gotten thus far — he’s suffering from a .200 BABIP against lefties — but there is reason to doubt the power will come if he continues with this ground ball and opposite-field approach.

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After going through the exercise, I’m not too concerned about the Red Sox’ problem against southpaws. All four of their main culprits are looking at positive regression at some point soon, and Betts and Pedroia should get completely back to normal. I’m most worried about Shaw, who is the only lefty on the list. Generally speaking, though, it’s just an unfortunate situation in which multiple players are slumping against lefties at the same time. Eventually, it will sort itself out and Boston will start to perform against pitchers of both handedness.