Through the first two weeks of the season, the Brewers bullpen struggled. In 42 innings, Milwaukee’s relief corps limped to a 4.75 ERA and 5.17 FIP. The group has experienced a turnaround in the weeks since, holding the line with a 3.67 ERA in 76 innings. There are a few reasons for the improved performance. Josh Hader is looking more like his vintage self, J.P. Feyereisen continues to put up zeros, and Devin Williams and Drew Rasmussen have pitched much better lately. However, one of Milwaukee’s best relievers has been one who gets little attention.
Brad Boxberger has fired 11 innings for the Brewers on the young season. He sits behind only Hader and Feyereisen in ERA (1.64) and FIP (2.69). Hader is the only member of the bullpen who is currently topping Boxberger’s 2.86 SIERA and 24.4% strikeout-minus-walk ratio. Boxberger leads the pack in WHIP (an impressive 0.64) and opponent barrel rate (3.8%).
All of these stats are eye-catching, but they can be subject to wild amounts of change this early into the season. The real story is not necessarily in the results, but in how Boxberger’s stuff has looked. When the Brewers inked him to a minor-league deal right as pitchers and catchers were reporting for spring training, it was not a major story. When he coughed up nine runs in the same amount of innings pitched and was released at the end of camp, no one batted an eye. However, the Brewers made sure to keep the former Rays closer around. The two sides agreed to terms on a new deal, and Boxberger reported to the team’s alternate training site until being promoted less than a week into the season.
In hindsight, it is evident why the Brewers were drawn to the veteran. Prior to the 2020 season, Boxberger worked out at Driveline Baseball and subsequently reached a deal with the Miami Marlins. With the Fish, his fastball was notably better than it had been in years. It previously had cutting action and very little vertical movement. In 2020, it had two more inches of rise than the average fastball thrown at a similar velocity. Speaking of velocity, Boxberger saw a significant improvement in that area as well. In his prime, his fastball sat in the mid-90s. Its average velocity began to steadily decrease in 2016, bottoming out at an average of 90 miles per hour in a failed 2019 stint with the Royals. With the Marlins, the veteran showcased a notable velocity boost, averaging 92.5 miles per hour. In short, Boxberger went to Driveline and left with his best fastball in years, if not his best one ever.
Those improvements have continued with the Brewers, who have become known for their high-tech pitching lab and success in the area of pitching development. His fastball now has elite rise—three inches better than average. At age 32, Boxberger’s fastball is averaging 93.9 miles per hour, which is the hardest he has ever thrown in his career. In 2020, the active spin on his heater (the percentage of a pitch’s spin rate that contributes to the movement on that pitch) was 89%. This year, that figure has shot up to 94%. The new fastball has been an extremely effective weapon, holding opponents to a .201 wOBA and .286 xwOBA, the latter of which is a career-best.
Just as notably, Boxberger has been limiting free passes to start the season. Control problems and walks have long been a thorn in his side. For his career, he has walked 11.9% of hitters he has faced. This season, he is issuing a base on balls just 4.9% of the time. The only full season in which the right-hander has kept his walk rate below the 10% mark was 2014, which was arguably the best season of his career.
Boxberger has provided versatility out of the bullpen early in the season, pitching anywhere from the sixth inning to the ninth, and Craig Counsell has handed him the ball in a variety of situations. He has held leads in the middle and late innings. In Philadelphia, he twice kept the Brewers in games that they were losing by one run. The minor-league signing has tallied one save and four holds in 12 games.
Boxberger’s shiny 1.64 won’t hold up for much longer. His .160 BABIP and 90.9% strand rate indicate that some correction is coming as his sample size of innings pitched increases. However, he is throwing harder than ever before, striking guys out, limiting free passes, and while his hard contact rate is rather pedestrian, he is missing barrels. He has three ERA estimators—xERA, FIP, and SIERA—that currently check in below 3.00. While there has been some good fortune involved, the metrics agree that his performance to start the year has been well above average.
Results from 11 innings of relief work mean little to nothing. However, it doesn’t take more than a few weeks to draw conclusions about how a pitcher’s stuff looks and take note of obvious changes in velocity and the shape of his pitches. It is clear that Boxberger’s stuff looks the best it ever has, a continuation of a trend that began last season. As the season continues, the veteran right-hander could find himself thrust into more high leverage situations. While J.P. Feyereisen has deservedly seen much of the spotlight in the bullpen thanks to his hot start, Brad Boxberger is also worth paying attention to. The early signs point to him being a successful bargain acquisition for David Stearns and Matt Arnold.
Statistics courtesy of FanGraphs and Baseball Savant.