George Kirby's shoulder
George Kirby is injured.
The Mariners announced on Friday that Kirby will begin the season on the injured list. His shoulder is inflamed. Justin Hollander says there is no structural damage. He cites an MRI. He said Kirby didn't want to be shut down.
“In the outings, he is throwing the ball well — same velocity as you would expect," Hollander said. "He just hasn’t felt like he’s bouncing back great.”
Kirby pitched on February 26. His average fastball velocity matched his 2024 numbers, however, his fastball averaged 97.2 mph in the first inning (three total pitches) and 95.4 mph in the second inning (five total pitches).
At minimum, Kirby will miss the first two turns through the rotation. But as John Trupin at Lookout Landing points out, shoulder inflammation "has presaged more lengthy issues for many hurlers." I looked up pitchers with "shoulder inflammation" in the Recovery Dashboard on Baseball Prospectus:
There have been 370 pitchers who missed time with "shoulder inflammation" since 2016
125 (about 1/3) of pitchers with shoulder inflammation had a final injury description other than shoulder inflammation (impingement, tendinitis, or bursitis)
The average pitcher with shoulder inflammation returned after 50 days; the median pitcher returned after 34 days
54.3% returned within four weeks
81.6% returned within eight weeks
11.3% required more than four months to return
10.1% of pitcher injuries are described as shoulder inflammation
12.7% of pitcher shoulder injuries required surgery, although the initial injury requiring shoulder surgery is not obvious on the dashboard
Only elbow injuries (65 days on average; 46 days median) sidelined pitchers longer
Emerson Hancock will likely take over as fifth starter until Kirby returns. Jake Mailholt at Lookout Landing recently outlined Hancock's new pitch arsenal.
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