A look at the Red Sox’ defensive struggles

With the regular season officially behind us, it’s quite obvious that this year did not end in happy fashion. After a 108-win campaign and a World Series trophy in 2018, the Sox finished just 84-78 this year, and 19 games behind the first place Yankees. Call it a down year or a World Series ‘hangover’ if you want, but this team had some major problems. One of these problems, and probably the least discussed relative to its impact, was their defense.

The Red Sox’ pitching was frequently faulted as the main issue with the 2019 team, but they were done no favors by the defense. As a team, the Sox had a 4.70 ERA, but also a 4.28 FIP (Fielding Independent Pitching, which attempts to strip out the role of defense and luck). The only other team with this wide of a margin between their ERA and FIP was the Detroit Tigers, who had with the worst record in the majors. This margin is at least partially explained by the Red Sox’ poor defensive efficiency, which finished at .673. Defensive efficiency measures the percentage of balls put in play that are converted into outs, and the Sox were among the bottom 5 teams in the league for this metric.

Who can the blame be attributed to? The biggest culprit, by one measure, is none other than offensive superstar Xander Bogaerts. As great as he was offensively, Xander was graded out horrendously on the defensive side of the field, accumulating -20 defensive runs saved (DRS), good for last in the MLB among qualified shortstops. Amazingly, JD Martinez and Eduardo Nunez were also major problems in the field despite their relatively few appearances. With just 39 games played each, they still had a combined -16 DRS. Lastly, youngster Rafael Devers was another liability in the field, with -5 DRS, but his improvement from last year (when he finished with -13 DRS) and offensive production gives him some wiggle room in my eyes.

Another potential culprit for this Sox defense was their shifting decisions. Weirdly, the Red Sox shifted just 38 total times all season against right-handed hitters (RHH), as opposed to a playoff team like the Dodgers, who shifted over 1300 times against righties. Not surprisingly, against RHH with runners in scoring position, the Red Sox allowed the most hits in the majors on ground balls (balls a shift would hopefully stop). The Dodgers gave up the fewest hits in baseball in those situations.

Despite the lack of shifting against righties, the Red Sox shifted 1104 times, almost 50% of all Plate Appearances, against left-handed hitters. Here, the Red Sox gave up the FEWEST hits in baseball on ground balls. One has to wonder the logic behind the choice to shift so heavily (and effectively) against lefties, but not at all against righties.

To conclude, a necessary goal for 2020 is to improve the defense, whether it’s better decision making regarding shifting or pursuing defensive-minded free agents. Next year’s team will likely look very different than this year’s, but long-term assets like Xander Bogaerts and Rafael Devers need to show progression, especially if defensive anchor Mookie Betts ends up on the offseason trade block.