While many Red Sox fans were excited that Adrian Gonzalez and Carl Crawford were added to the lineup over the winter, there were others wondering if Boston was becoming far too lefty-heavy. With so many lefties in the lineup, they would leave themselves vulnerable against southpaws, and in a park that already hurts the production of lefty hitters. Given there wasn't a whole lot to worry about on the Red Sox roster heading into the year, this viewpoint continued to swell in popularity, because fans and analysts had to be concerned about something, didn't they?
When the Red Sox started out 2-10 and had lost a few games against lefties (and reverse-split right-handers), the swell grew to a tidal wave of complaints about how Boston was doing it wrong. The fact that nearly three-quarters of the innings in the majors are thrown by right-handers was almost roundly ignored--setting up your lineup for the express purpose of dominating lefties makes no sense, given how little teams face them in a relative sense. Boston was, in fact, doing it right.
Now we're nearly halfway through the season, with Boston having played its first 65 out of 162 games and coming up against a reverse-split right-hander in James Shields tonight, giving us an excuse to look at how they have done against those dreaded southpaws to this point.
The team's left-handers are predictably performing worse against southpaws than they are against right-handers, to the tune of .261/.325/.390, compared to .294/.357/.499. While that looks poor on the surface, it isn't at all, for two reasons. One, lefties in the lineup have faced lefty pitchers in just 15 percent of the team's total plate appearances. Two, the 714 OPS that Boston's lefties have put up against their fellow southpaws is 23 percent better than the average performance against lefties.
Almost every lefty struggles against left-handers, but Boston lefties struggle less as a unit, and that is with Carl Crawford doing his best to never get a hit off of lefties, ever. Comparatively, it's the right-handers who have been more problematic for Boston against their same-handed counterparts, as their 680 OPS is just two percent better than the league average for righty-on-righty action.
The thing is, by loading up the lineup with so many lefties, Boston has been able to beat on right-handers--the predominant species of arm in the game--29 percent better than the league. That lefty hitter vs. righty pitcher match-up has comprised 49 percent of Boston's plate appearances on the year.
Their lefties are better than your average lefty when it comes to hitting southpaws, and they also crush the opposite-handed opposition. The season isn't over yet, but it looks like playing the numbers to construct a lineup has worked out for these first place Red Sox, and that loading up on lefties is a feature, not a bug.