Bullpen Profile: Tampa Bay Rays Closer Brad Boxberger

The American League East has some of the finest bullpen arms in MLB, from Craig Kimbrel in Boston to Darren O’Day in Baltimore. The Tampa Bay Rays boast a robust starting rotation with even more talent in the minor leagues, but their fresh-off-the-DL closer is still a solid option for the Rays. Ian York uses PITCHf/x and his unique charts to demonstrate how Brad Boxberger utilizes his pitches to be an effective closer.

Brad Boxberger returned from the disabled list this week after previously returning and making one appearance before having to be placed back on the shelf. The Tampa Bay Rays’ closer in 2015 led the AL in saves with 41, which may suggest that he is one of the better relievers in baseball. In fact, while he’s not terrible by any means, he’s probably no more than a mid-tier closer. In 2014, Boxberger was the Rays’ setup man for closer Jake McGee, but McGee underwent elbow surgery before the 2015 season and Boxberger was given the closer’s role. Even after McGee returned from the disabled list in mid-May, Boxberger kept the 9th inning, with McGee mainly pitching in the 7th and 8th.

Boxberger mainly throws a four-seam fastball (“FF”, in the charts below), a changeup (“CH”), and an occasional curve (“CU”) that he usually throws to right-handed batters. The fastball is just about league-average for speed (93.7 mph) and moves somewhat less than average (3.3 inches break length, compared to 4 inches average for right-handed pitchers), but it is well separated from his change (average speed 80.8 mph):

He also throws a slider (“SL”) that he almost completely dropped in 2015, and according to PITCHf/x (but not Brooks Baseball) he may sometimes throw a cutter (“FC”). He has been simplifying his repertoire for several years, increasingly focusing on his fastball/changeup combination:

In 2015, he showed the same trend in miniature, adapting to the closer’s role by cutting back on his curve and using his fastball more as the season progressed:

Boxberger’s results in 2015 were good (41 saves, 4 wins, 2 holds) but not great (10 losses, 6 blown saves). His ERA was decent (3.71) and he struck out 10.57 batters per 9 innings (30th among 137 qualifying relievers), but his relatively poor FIP (4.26) and WHIP (1.365) suggest that he was somewhat lucky. In several outings, he gave up multiple runs, and his walk rate (BB/9 of 4.57) was 11th worst among 137 qualified relievers, according to FanGraphs. By comparison, Jake McGee had better numbers in 2015 (ERA 2.41, FIP 2.33, and .938 WHIP) and 2014 (1.89, 1.73, and .897). However, the Rays were probably worried about his health as closer, and were willing to use the better pitcher in more flexible ways.

The reason for Boxberger’s high walk rate is not immediately obvious when we look at his pitch locations. His fastballs and his changeups seem to have good location inside or close to the margins of the strike zone. As illustrated by the heatmaps below, many of Boxberger’s changeups end up outside the strikezone (especially to left-handed batters), but they draw many swinging strikes at pitches outside the zone. (These charts are from the umpire’s viewpoint. The grey polygon shows the strike zone as it was called in 2015.):

His fastball was called a ball 32.1% of the time, compared to 34.2% for the average right-handed pitcher’s fastball, and his change was a ball 37.4% of the time, exactly league average.

Where Boxberger strays from league average is in his pitch selection with a 3-ball count. In these counts, the average RHP increased his fastball use from from 63.1% to 76.5%. Boxberger only slightly increased his fastball use (61.7% to 67.5%), and his changeup frequency stayed almost constant (34% to 32.5%). What’s more, Boxberger doesn’t improve his strike frequency when there are three balls. (The same things happen (or don’t happen) when ahead vs. behind in the count, although, of course, it’s less pronounced.) Pitchers typically go to their fastball in the 3-ball counts because they are more likely to throw strikes with it, but they also increase their pitch accuracy in general, reducing the frequency of balls by 10-15%. Boxberger can’t, or won’t, do this; he is about equally likely to throw a ball when there are already three balls, as when there are fewer than three:

If this is, for some reason, a deliberate strategy on the part of Boxberger or his catchers, then he may be able to reduce his walks by taking a more conventional approach. Since his BB/9 in 2014 was significantly lower than in 2015 (2.8 in 2014 vs 4.7 in 2015), he may be able to improve his command and strengthen his main weakness. If not, he is likely to remain a decent but unspectacular option for the closer role in Tampa.

Ian York uses the PITCHf/x to monitor the strike zone, highlights great performances, monitors league-wide trends and tracks the performances of some interesting young hitters.

Follow Ian on Twitter @iayork.

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Ian is an immunologist and virologist who lives in Atlanta with his wife and two sons. Most of his time is spent driving his kids to baseball and soccer games, during which he indoctrinates his children on the glories of Pedro Martinez, the many virtues of the Montreal Expos, and other important information.