What to Expect in George Kirby’s Return to Mariners Rotation
All-Star pitcher George Kirby will make his season debut against the Astros on Thursday, Mariners manager Dan Wilson confirmed Wednesday morning. Kirby was the first of three Mariners starting pitchers to land on the injured list this season, later being joined by Logan Gilbert (right elbow flexor strain) and Bryce Miller (right elbow inflammation), and missed the majority of Spring Training with right shoulder inflammation.
As a result of the significant time he missed, Kirby was required to make three rehab starts with Triple-A Tacoma over the past few weeks. After all, he only threw one inning in a real spring game all the way back on February 26. Not only did he need to work back from injury, but he also needed to generally ramp up for the season ahead. In general terms, Kirby is likely a month or so behind the rest of Seattle’s current rotation.
Over the course of his rehab stint, Kirby completed 10 full innings while giving up eight earned runs on 15 hits (three home runs) with 13 strikeouts and a pair of walks. The large amount of runs Kirby allowed shouldn’t send up any red flags; like with any other pitcher making an appearance in spring ball or on a rehab stint, this can easily be chalked up to him working on specific things rather than strictly attacking opposing hitters. Matt Brash, who’s sporting a 0.00 ERA in five appearances after giving up five runs during his respective rehab assignment, is a great — and recent — example of why very little stock should be put into the counting stats.
The more relevant takeaway from Kirby’s three starts is that his velocity was where it needed to be, and more importantly sustained the deeper he got into his pitch count. Here’s a look at how his stuff fared overall, per Prospect Savant:
The Mariners haven’t announced what kind of limitations might be placed on Kirby in his first few starts back with the big-league club, but some educated guesses can be made based on his usage in Triple-A. He was able to complete four innings on 64 pitches in Albuquerque last Friday, which would seem to indicate his next threshold will be somewhere in the 70-80 pitch range.
Therefore, unless the Astros are incredibly aggressive early on and hit into some quick outs, the Mariners will have to prepare to cover four or more innings with their bullpen Thursday night. At the very least, they’re better suited to handle such an outcome than initially expected; they were able to avoid a doubleheader with the White Sox on Wednesday and only needed to use four pitchers during their scheduled bullpen night on Tuesday.
No corresponding move will be made to clear room on the 26-man roster for Kirby until Thursday, though it will likely either be one of two relievers: Jesse Hahn, who was selected Wednesday morning to take the place of Tuesday night spot-starter Casey Lawrence, or Troy Taylor, who’s struggled mightily in his handful of appearances this year. The rotation will re-slot behind Kirby, with Emerson Hancock, Bryan Woo, Luis Castillo, and Logan Evans going in that order.
