The Brewers came within one win of a trip to the World Series last year thanks in part to the performance of a dominant bullpen that helped to offset a shaky, injury-wracked rotation. Thus far this spring, however, that bullpen has borne the brunt of the Brewers’ injuries. With Jeremy Jeffress having already started the season on the injury list due to shoulder weakness, the team just suffered an even bigger loss, as Corey Knebel revealed on Friday that he will undergo Tommy John surgery.
The 27-year-old Knebel originally suffered a partially torn ulnar collateral ligament in 2014, while pitching for the Rangers’ Triple-A Round Rock affiliate. He was just over a year into his professional career at that point, having been chosen as a supplemental first-round pick by the Tigers out of the University of Texas in 2013, then dealt to the Rangers in a July 2014 trade involving Joakim Soria. The injury wasn’t severe enough to require TJS, so he rehabbed it and kept pitching, establishing himself in the majors after being traded to the Brewers in the Yovani Gallardo deal in 2015, then taking over closer duties from the struggling Neftali Feliz in 2017. That year, he earned All-Star honors while saving 39 games, making an NL-high 76 appearances, and pitching to a 1.78 ERA, 2.53 FIP, and 2.7 WAR; the last mark ranked fourth in the majors among relievers with at least 50 innings.
The 2018 season was a different story for Knebel. He made just three appearances before missing a month due to a left hamstring strain, and pitched so erratically that he was sent back to Triple-A Colorado Springs with a 5.08 ERA and 4.29 FIP in late August. Fortunately for the Brewers, he was thoroughly dominant upon returning, holding batters to a .096/.175/.135 line while striking out 33 of the 57 he faced in 16.1 scoreless innings through the end of the regular season, then striking out 14 out of 33 hitters over 10 postseason innings while allowing just one run. Overall, his 3.58 ERA was more than double his 2017 mark, though his 3.03 FIP wasn’t so far removed; in both seasons, he posted top-five strikeout rates (40.8% in 2017, 39.5% last year) and top 10 K-BB% (27.8% and 29.6%, respectively), with a jump in home run rate (from 0.71 per nine to 1.14) the big difference. Still, between that and a lesser workload (from 76 innings to 55.1), his WAR dropped from 2.7 to 1.0.
Knebel had been diagnosed with additional UCL damage this spring after reporting discomfort following a March 17 Cactus League appearance. Faced with the decision to try rehabbing again, which carried with it the possibility of costing himself not only the 2019 season but a good chunk of 2020, or submitting to surgery now and targeting the beginning of next year for his return, he chose the latter route. According to Jon Roegele’s Tommy John Surgery List, he’ll be the fifth major league pitcher to undergo the procedure this spring, after the Blue Jays’ Mark Leiter Jr., the Mets’ Drew Smith, the Diamondbacks’ Silvino Bracho, and the Tigers’ Michael Fulmer.
With Knebel out, the Brewers will again have to summon a level of resourcefulness. Last year, manager Craig Counsell used both Jeffress and Josh Hader to save games when Knebel went down. With Knebel finishing with 16 saves, Jeffress 15, and Hader 12, the team became just the fifth squad of the past 14 seasons with a trio of pitchers in double digits, along with the 2014 Angels, ’15 Mariners, and ’16 and ’18 Astros.
The save stat only hints at Counsell’s departure from bullpen orthodoxy in convincing his players to move beyond the typical setup/closer labels in favor of “go in and get outs.” Hader, in his first full season, made the All-Star team while working in a pattern reminiscent of Andrew Miller during the 2016 postseason. Of his 55 appearances, he entered in the eighth inning or earlier 50 times, and got more than three outs a league-high 33 times. Jeffress entered in the eighth inning or earlier in 52 of his 73 appearances, and got four or more outs 18 times. Seven of Hader’s saves, five of Jeffress’, and even two of Knebel’s were of four outs or more, and four other Brewers relievers each notched one multi-inning save for an league-high 18.
Jeffress, who pitched to a 1.29 ERA and 2.78 FIP in 76.2 innings last year, left a March 6 exhibition with shoulder soreness after throwing just 83-84 mph. He began the season on the injury list but could go out on a rehab assignment later this week, and is expected back sometime in mid-April. Fortunately, Hader has resumed his dominant form, retiring the first nine batters he’s faced this year, seven via strikeout.
The most obvious solution to replace Knebel would be to sign Craig Kimbrel. But while Milwaukee has checked in on the free agent closer, and while owner Mark Attanasio described the Brewers — who set a franchise-record with a $122.5 million Opening Day payroll — as “all in now” when the team signed free agent infielder Mike Moustakas, it doesn’t sound as though spending another $18 million on Kimbrel is in the cards, so solutions will have to come from within.
One option that’s already out is Bobby Wahl. A 27-year-old righty who can touch 99 mph, Wahl was acquired from the Mets in the Keon Broxton trade, but tore his right ACL in early March and is done for the year. Taylor Williams, who struck out more than a batter per inning last year as a 26-year-old rookie, has high-leverage stuff including a fastball in the 95-98 range, but his command is limited. Chase Anderson, who was bumped from the rotation after a subpar 2018 (3.93 ERA, 5.22 FIP), could help; contributor Devan Fink recently offered a look at the way shortening his repertoire could reduce his vulnerability to the long ball. Meanwhile, the Brewers’ current rotation includes three young pitchers who worked out of the bullpen last fall, namely Corbin Burnes, Freddy Peralta, and Brandon Woodruff. They’ve joined Jhoulys Chacin and Zach Davies in the rotation, but if and when Jimmy Nelson returns, one pitcher from among that trio could transition back to relief work. Nelson missed all of last season while recovering from September 2017 surgery to repair labrum and rotator cuff tears, and he’s been slowed this spring by elbow soreness, so that plan isn’t happening immediately.
As the Brewers sort through their options, it’s worth remembering just how hard it is to maintain a strong bullpen from year to year, whether the cast of characters remains largely the same or turns over. Via our splits, the year-to-year correlations for team bullpen performance are much lower than for rotations. For the 1998-2018 period:
Admittedly, this is something of a crude measure, but it does illustrate a point. Given collections of pitchers who are generally less talented and more fungible than starters, and who are throwing relatively small samples of innings, the year-to-year performances for the group wind up being more volatile. Since the start of the 1998 season, just 93 teams out of 600 (15.5%) have gotten at least 3.9 WAR from their bullpens — a mark that’s generally good enough to rank in the upper third of the majors — in back-to-back seasons. With 4.1 WAR from their bullpen in 2016 (Counsell’s first full season), then 4.4 in 2017 and 6.6 last year, the Brewers already account for two of those 93 repeaters.
Perhaps they’ve got another strong season in them, particularly if Jeffress comes back strong and if Hader can again hold up to the kind of multi-inning workload that pushed him to 81.1 frames last year. Certainly, Counsell has shown a deft touch during his tenure, and likewise for general manager David Stearns in finding fresh arms. Still, in a tight NL Central race, any disadvantage could prove the difference between making the playoffs and missing out, and in losing Knebel, the Brewers have just one more to overcome.
Brooklyn-based Jay Jaffe is a senior writer for FanGraphs, the author of The Cooperstown Casebook (Thomas Dunne Books, 2017) and the creator of the JAWS (Jaffe WAR Score) metric for Hall of Fame analysis. He founded the Futility Infielder website (2001), was a columnist for Baseball Prospectus (2005-2012) and a contributing writer for Sports Illustrated (2012-2018). He has been a recurring guest on MLB Network and a member of the BBWAA since 2011. Follow him on Twitter @jay_jaffe.