The White Sox announced Monday that they’ve placed right-hander Joe Kelly on the 15-day injured list due to a groin strain and selected the contract of right-handed reliever Keynan Middleton. Right-hander Jonathan Stiever was outrighted in order to open a 40-man spot for Middleton. Stiever hasn’t been previously outrighted and doesn’t have three years of MLB service time, so he can’t reject the assignment. He’ll remain with the organization now that he’s cleared waivers.
Middleton, 29, signed a minor league deal over the winter and didn’t initially win a spot in Chicago’s bullpen, pitching to a 6.00 ERA in nine spring innings. He’s opened the year in Charlotte with a trio of scoreless frames, punching out three of the 11 batters he’s faced and also walking a pair.
The White Sox will be Middleton’s fourth big league club. He spent the first four seasons of his career with the Angels, looking at one point like a potential building block in the relief corps in Anaheim. Middleton debuted with 58 1/3 solid innings back in 2017 (3.86 ERA, 25.6% strikeout rate, 7.3% walk rate) and showed a high-octane fastball that averaged 97 mph.
Middleton started the 2018 season with an even stronger 2.04 ERA in 17 2/3 frames but saw diminished velocity while his strikeout and walk rates trended in the wrong direction. He was placed on the injured list in May with what the team discovered some damage in his ulnar collateral ligament. He underwent Tommy John surgery just a few days later. That wiped out the remainder of his 2018 season, and while Middleton returned with a clean 1.17 ERA in 7 2/3 innings the following year, he walked more hitters (seven) than he struck out (six) and was working with a fastball sitting at 94.2 mph.
In the three seasons since, Middleton’s velocity has fluctuated greatly, but his results with the Halos, Mariners and D-backs have been similarly below par. Overall, since returning from Tommy John surgery, the right-hander carries a 4.66 ERA with a 19% strikeout rate and 11.9% walk rate that are both worse than the league average. In the aggregate, his post-TJS fastball has sat at 95.6 mph, but that includes year-to-year averages that are all over the map: 94.2 mph in 2019, 97.2 mph in 2020, 95.6 mph in 2021 and 94.8 mph in 2022. Along the way, he’s encountered biceps, elbow and ankle injuries.
As for the 34-year-old Kelly, he’s gotten out to a rough start, yielding three runs on four hits and a walk through his first 2 2/3 innings of the 2023 campaign. He’s playing out the second season of a two-year, $17MM contract that hasn’t panned out as either he or the White Sox hoped. Biceps and hamstring injuries limited the former Red Sox and Dodgers hurler to 37 innings last year, during which he posted an unsightly 6.08 ERA with a career-worst 13.5% walk rate. He’ll now head to the injured list for the third time in just over one calendar year with the South Siders.
Kelly, of course, has a much better track record prior to his time with the ChiSox. From 2017-21, he tossed 229 innings of 3.62 ERA ball, and he was a postseason hero for the 2018 Red Sox, tossing 11 1/3 innings of one-run ball with a 13-to-0 K/BB ratio in the postseason during their march to an eventual World Series title.
Stiever, 26 next month, is a 2018 fifth-rounder who ranked among the White Sox’ best prospects from 2020-21 but has seen his stock tumble in recent seasons, in part due to health troubles. Stiever underwent lat surgery late in the 2021 season and spent nearly the entire 2022 campaign on the 60-day injured list as a result. He’s appeared in just 6 1/3 MLB innings, allowing 10 runs on 11 hits (four homers) and four walks in that time.
Because of those injuries and the lost 2020 minor league season, Stiever still has just 252 minor league innings under his belt. Seventy-nine of those have come at the Triple-A level, but he’s been tagged for a 5.47 ERA in that time. All but five of those 79 frames came during an ugly 2021 season, and Stiever has tossed a pair of scoreless innings so far to begin his ’23 season. He’ll remain in Triple-A and hope that better health brings about better results. If so, he could conceivably work his way back into the 40-man roster conversation at some point.