When Justin Steele went under the knife for UCL revision surgery last month, ending his 2025 season early, the pressure of carrying the load at the front of the Cubs’ rotation went from being shared between two All-Star southpaws to falling entirely on the shoulders of Shota Imanaga. Imanaga’s first eight starts of the year have generally gone quite well, as he’s pitched to a 2.82 ERA despite his peripherals regressing significantly (4.52 FIP, 4.69 SIERA) relative to last year’s dominant rookie campaign.
Unfortunately, his own season was at least temporarily derailed yesterday when Chicago placed him on the injured list due to a strained left hamstring. Fortunately, the Cubs and Imanaga appear to view the strain as a fairly mild one. Manager Craig Counsell suggested during his postgame interview yesterday (h/t Marquee Sports Network) that the outcome was “pretty good news” and that it was at least possible that Imanaga wouldn’t take much longer than a minimum stay on the shelf to recover. Even so, another starter will be needed to join Jameson Taillon, Matthew Boyd, Ben Brown, and Colin Rea in the rotation.
Perhaps the Cubs need look no further than the hurler at Triple-A who was already on the same schedule as Imanaga prior to the injury. Top pitching prospect Cade Horton, selected in the first round of the 2022 draft, has been nothing short of dominant so far this year. A consensus top-50 prospect in the sport, Horton has made six starts for the club’s Iowa affiliate this year and has posted a sparkling 1.24 ERA in that time with a strikeout rate of 30.6%. It’s the sort of dominance that will naturally lead to fans calling for a big league debut, and those calls have only grown louder in the aftermath of Imanaga’s injury. It’s hard to argue any pitcher currently on the big league roster has a higher ceiling than Horton, who sports a mid-90s fastball that touches 98 and a plus slider as part of a strong four-pitch mix.
For his part, Counsell told reporters (including Maddie Lee of the Chicago Sun Times) that Horton is “an option” to replace Imanaga in the rotation. With that being said, Counsell also noted that veteran right-hander Chris Flexen remains stretched out after recently having his contract selected from Triple-A ahead of a uniform opt-out opportunity in his contract on May 1. Flexen threw 54 pitches in three scoreless relief innings last week and sported a 1.16 ERA with a 22.3% strikeout rate in 23 1/3 innings of work at Triple-A before his contract was selected. A veteran of eight MLB seasons who also briefly pitched for the KBO League’s Doosan Bears, Flexen has generally been a roughly average swingman since he returned from South Korea with a 4.56 ERA (90 ERA+) in 582 2/3 innings of work.
His numbers fell off substantially over the past two years, but it’s hard to deny that he’s looked impressive since joining Chicago on a minor league deal. Still, there’s no question that Horton is the more talented pitcher with much higher upside. Horton seems likely to have a very successful career with the Cubs in the coming years, but there are other considerations that could tip the scale towards Flexen. The Cubs’ bullpen, which ranks bottom ten in the majors with a 4.37 ERA, has already been stretched somewhat by short starts from Rea and Brown this year. Horton would add another hurler who can’t be expected to pitch deep into games to the rotation mix, seeing as he’s maxed out at just 78 pitches this year. Flexen, meanwhile, has maxed out at 95 pitches and pitched into the sixth inning in three of his four full-length starts with Iowa.
Horton’s injury woes over the years, from Tommy John surgery in college to a subscapularis strain that cost him most of his 2024 season, have left the Cubs in a position where they’ll need to carefully manage the talented right-hander’s innings this year. For a team with postseason aspirations, it’s fair to wonder if calling him up in early May is the right call when his electric arm may be needed come October. On the other hand, however, it’s worth noting that Horton did not throw a single pitch after May 29 last year. Health for a pitcher is never guaranteed, so it’s possible the Cubs would be best off simply calling up Horton now while he’s pitching well and figuring out how to manage his innings later by either shutting him down at some point this year or moving him to the bullpen.
How do MLBTR readers think the Cubs should handle the vacancy in their rotation while Imanaga is out of commission? Should they turn to the high-upside prospect knocking on the door of the big leagues while he’s healthy and pitching well, or instead opt to use Flexen in order to manage Horton’s innings and preserve the bullpen? Have your say in the poll below:
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