Royals' Brad Keller diagnosed with thoracic outlet syndrome

Royals right-hander Brad Keller spent most of the 2023 campaign on the injured list due to a right shoulder impingement and though he was activated briefly early this month, he quickly found himself back on the shelf due to what the club described as “symptoms associated with thoracic outlet syndrome.” 

His placement back on the IL had already ended his 2023 season, but manager Matt Quatraro told reporters (including Jaylon T. Thompson of the Kansas City Star) that Keller has indeed been diagnosed with thoracic outlet syndrome. Quatraro added that Keller has not yet decided a course of action regarding his injury and figures to decide in the coming days about his path forward.

It’s brutal news for Keller, who is poised to depart the Royals for free agency once the 2023 season comes to a close. Keller looked to be a quality mid-rotation starter in the early seasons of his career, posting a 3.50 ERA and 3.90 FIP in 360 1/3 innings of work between 2018 and 2020. Unfortunately, he’s suffered a significant downturn in production since then, with a 5.14 ERA and 4.80 FIP across 314 2/3 innings since the start of the 2021 campaign. 

In that time, Keller’s walk rate crept up to 11.5%, well above the 9.1% figure he posted in the first three seasons of his career. While Keller was striking out more batters as well, it wasn’t enough to compensate for the additional walks, to say nothing of a sustained spike in the percentage of his fly balls leaving the yard for home runs in recent years. After posting an HR/FB of just 8% in the first three years of his career, that number spiked to 13% the last three seasons.

With less than two months until free agency figures to open, Keller faces a significant degree of uncertainty about the future of his career after spending his entire major league career to this point with the Royals. Surgery to correct TOS has rarely seen players return to the majors and enjoy success, with Stephen Strasburg and Chris Archer among the arms who have seen their careers impacted by the procedure in recent years. 

One example of a player who has returned effectively is Arizona right-hander Merrill Kelly, who stands as a prime example of the fact that not all types of TOS have the same long-term outlook.

More from around the AL Central…

• The Twins could welcome right-hander Chris Paddack back to the major league roster as soon as Sunday, according to Dan Hayes of The Athletic. Paddack, 27, has been on the IL since last spring after undergoing Tommy John surgery, but has long been been considered a possible late-season option for Minnesota’s pitching staff. It seems that possibility is on the verge of coming to fruition, with The Athletic’s Aaron Gleeman noting that Paddack is expected to contribute as a reliever out of the bullpen rather than a member of the rotation upon being activated. Paddack looked impressive in his most recent rehab outing at Triple-A, where the righty struck out five on two hits and a walk across three scoreless innings of work.
• The Guardians have placed left-hander Logan Allen on the 15-day injured list with left shoulder inflammation, per MLB.com’s Mandy Bell. The move brings an end to Allen’s rookie season. It was an impressive start to the young southpaw’s career, as he posted a solid 3.81 ERA (110 ERA+) with a 4.20 ERA across 24 starts with the Guardians this year. Allen and fellow rookies Tanner Bibee and Gavin Williams are the latest young arms to slide into the club’s rotation from their farm system, and figure to join more established arms like Shane Bieber and Triston McKenzie as quality rotation options as Cleveland looks ahead to the 2024 campaign.