As far as things stand on the field with the roster, most of the conversation around the Red Sox looking ahead to the 2020 season relates to the pitching. Clearly, there is good reason for that. The pitching was their undoing in 2019, and if you were to isolate one key for the 2020 campaign, few people would choose something other than the rotation. That group has questions with both its health and its performance even if it is healthy.
At the bottom of the list would probably be the lineup. It’s certainly not a perfect group — and we’re not even sure if its complete yet — but it certainly has the pieces to be one of the better lineups in the game. Even last season, which was by and large terrible for the team overall, they were an effective unit. Boston ranked fourth in runs scored and sixth in wRC+ in 2019. They weren’t up there with the elites, but they were firmly at or near the top of the second tier. Despite the success, there was a weakness (relatively speaking) with their production against left-handed pitching.
This seems strange considering how good they were overall and how good they are from the right side of the plate. I mean, three of their top four hitters (and probably their top three) are J.D. Martinez, Mookie Betts and Xander Bogaerts. Not too many teams can boast that kind of talent from the right side in the top half of their lineup. Despite that, they were simply a league-average offense against southpaws in 2019, finishing with a perfect average 100 wRC+ and ranking 14th in baseball. It’s not the kind of weakness that can derail a season, of course, but considering how mystifying it is with their talent as well as the pitching being so bad that they needed every run they could squeeze across the plate, it certainly contributed to their struggles.
Last season no longer matters, though. As we look ahead, we have to wonder if this is something to worry about long-term or if this was just a blip on the radar. Looking at the team as a whole, they walked a bit less than you’d want, but not egregiously so. Their biggest issue seemed to be with batting average on balls in play, where they ranked 22nd. It’s easy to look at that and chalk it up to bad luck — especially considering the aforementioned talent — but we’re smarter than that. These things demand a little more information, and sure enough they also ranked near the bottom of the league in both hard-hit rate (25th) and line drive rate (26th), both per Fangraphs. That’s not to say there was no bad luck involved, but the Red Sox certainly didn’t help themselves, either.
In terms of individual players, Mookie Betts was surprisingly the most disappointing on this front. He wasn’t bad against lefties, finishing with a 116 wRC+. It’s just that he wasn’t great like we are used to him being. In 2018, for example, he finished with a wRC+ almost 100 points higher at 212. Much like the team, Betts’ issue was with batted balls. In fact, his plate discipline was fantastic against lefties with a 15 percent walk rate and 11 percent strikeout rate. On the other hand, he finished with a .281 BABIP and a .187 Isolated Power. The good news here is that we’re talking about fewer than 200 plate appearances and his batted ball data was almost identical to what it was against righties, against whom he had a .320 BABI and a .246 ISO. It’s hard to believe Betts won’t be Betts against lefties again in 2020.
Perhaps a more concerning name here is Rafael Devers. He obviously had a huge breakout at the plate last season, but he still was below-average against lefties with an 89 wRC+. His BABIP was fine (.302), but his power dropped off and, more importantly, he walked less than three percent of the time. Looking at his swing chart, it’s pretty clear he has a weakness that is easily exposed: Just chuck breaking balls down and away.
This is also backed up by the Statcast data, as Devers had an expected wOBA of just .247 against breaking balls from lefties and an actual wOBA .262. This was actually an improvement on 2018, too. He only saw these pitches 32 percent of the time last year, but I would expect that number to rise in 2020. It’s up to him to make the adjustment.
Those are the two keys to the lineup as a whole improving in this area, but there are other contributors, too. Xander Bogaerts had a 130 wRC+ against lefties, and while that’s nothing to sneeze at we know he can be elite at the plate. Michael Chavis was rough with an 85 wRC+, and if he doesn’t improve I think Bobby Dalbec will be even more demand for time at first base. I would also note that, if Chavis can improve against lefties and gets work in left field, that would be helpful for getting Jackie Bradley Jr. on the bench against lefties (assuming he’s still with the team). As I said at the top, the pitching is what will make or break this Red Sox team. Scoring runs is a nice way to offset any pitching woes, though, and for as solid as the offense was last year there is reason to think they should improve against lefties in 2020, with Betts and Devers holding the keys.