After spending the last two seasons in the White Sox starting rotation, Michael Kopech is headed back to the bullpen. It is a smart move for the White Sox that puts Kopech in the best position to be successful.
Kopech has started 60 games for the White Sox during his four seasons in Chicago which have netted inconsistent results. He coming off a season where he had a 5.43 ERA in 27 games starter. During that stretch, he failed to make it past the fifth inning in 19 of those starts.
His failure to make it into the sixth inning consistently puts extra stress on a White Sox bullpen that will likely be expected to eat a bunch of innings. The White Sox already have several young arms vying for a spot in the rotation and growing pains are to be expected. It was a point that White Sox general manager Chris Getz echoed when speaking to reporters on Thursday.
“We thought we were going to run the risk of taxing our bullpen and the remainder of our pitching staff. So we’re looking for starters who can be more efficient on the front end to help navigate the season,” Getz explained.
There is no question that Kopech has the stuff to be an effective pitcher in the big leagues, but the hard-throwing right-hander has struggled to go deep into games. Some of that stems from his struggles in the first inning. Last season Kopech posted a 6.75 ERA in the first inning. He also allowed 24 walks in the opening frame, which was the most of any inning he pitched in last season.
The inability to throw strikes has hindered his ability to work deep into games. Kopech’s 15.4% walk rate ranked in the bottom one percent of the league. In 2022, he walked 11.4 percent of opposing batters, ranking in the bottom 8% of the league.
The best version of Kopech White Sox fans have seen was when he is trotting out of the left-field bullpen. In 2021 he boasted a career-best 36.1% strikeout rate, which placed him in the top 3% of the MLB. Kopech averaged 13.01 strikeouts per nine innings out of the bullpen, the third-highest total in franchise history. He also limited his opponent’s expected batting average against him to .185 which ranked in the top 5% of the league.
Michael Kopech on moving to the bullpen and Dylan Cease getting traded. pic.twitter.com/lPWmIB4Dxn
— Chuck Garfien (@ChuckGarfien) March 14, 2024
During his lone season in the White Sox bullpen, Kopech had a career-best 3.53 ERA, which might have been even better if he didn’t have the 27th-ranked defense behind him at the time. His 2.83 expected ERA that season placed him in the MLB’s top 7%. Those numbers could have been even more impressive if not for a couple of rough outings. Fourteen of the 24 runs he allowed as a reliever came over three outings.
Once he was moved into the rotation his average fastball velocity dropped from 97.1 mph in 2021 to 94.9 mph in 2022. During his 2021 campaign, his four-seam fastball had a Run-Value of 5 and was arguably his most effective pitch. His four-seamer produced a 34.1% strikeout rate and 34.1% whiff rate and seemed to explode out of his hand. He reached triple digits with his fastball 19 times and had 243 pitches clocked at 98 plus. Opponents struggled to the tune of a .196 expected batting average against it.
Flash forward to 2023 and Kopech’s fastball is a shell of itself. Opponents expected batting average off Kopech’s fastball jumped to .240 while its strikeout rate dipped to 21.1%. Meanwhile, its Run-Value plummeted to -4. His slider also suffered once he was moved to the rotation.
Kopech produced a 42.4% strikeout rate when throwing his slider in 2021. The following year that strikeout rate dropped to 19.1%. Last season his slider netted him a 26.6% strikeout rate and 24.4% whiff rate, which was the highest of his four-pitch mix. But it was still nowhere near the level it was in 2021.
The bulk of Kopech’s struggles out of the bullpen came later in the season. Before the All-Star break, he owned a 1.53 ERA. During his 26 appearances after the All-Star break, he produced a 5.56 ERA. An argument can be made that fatigue was a factor.
That won’t be as big of an issue now that he has been building up as a starter and will have less of a workload in the bullpen, something that Getz brought up when discussing the White Sox decision to move Kopech back to a reliever role.
“We hope the smaller bite at the apple so to speak in reliever outings, whether it be one or two innings is going to be easier to accomplish for Michael and be better for the White Sox,” Getz told reporters on Thursday.
While it is frustrating that he never turned into the ace many fans envisioned when the White Sox traded for him, he still has a good opportunity to help the team win games.
Building Kopech’s confidence back is key. He often nibbled around the zone last season and failed to throw his pitches with conviction. This resulted in a high walk rate and trouble limiting big innings. Ultimately a move to the bullpen should allow Kopech to throw harder, think less, and hopefully rediscover why he was once considered the ninth overall prospect in baseball.
