Status Report: Mariners RHP George Kirby
Getting solid production from a rookie starter is not something a team should count on; it just doesn’t happen often. The Mariners were lucky to receive strong contributions from Logan Gilbert last year, and George Kirby has followed suit this year. Even after a disastrous start against the Orioles on Monday night, Kirby has been very good in his first major league action.
Taking a look at Kirby’s Baseball Savant page, nothing stands out immediately besides a walk rate that ranks in the 99th percentile in MLB. Strike throwing is Kirby’s calling card and he has pounded the zone effectively this season, allowing only seven walks to 49 strikeouts so far in 53 innings pitched.
Comparatively, Logan Gilbert walked 10 and punched out 53 in his first 10 big league starts. Kirby is running an ERA of 4.08, compared to the 3.50 of Gilbert. The numbers are awfully close, so can Kirby follow the blueprint?
The right-hander from Elon has given up 12 home runs this year, which is about one every 5.1 innings pitched. His fastball averages 95.6 MPH, but it does come with the same spin and extension Gilbert possesses. Kirby will have to locate his fastball well or he will fall in trouble and in danger of the long ball. Extracting more value out of his fastball spin is one way for him to make a jump.
Gilbert made it through most of last year by relying heavily on an impressive fastball. Kirby does not have the same capability, but his advantage lies in his command.
Kirby has a fastball, changeup, slider and curveball mix. The 24-year old can throw all of these for strikes and much more reliably than Gilbert could last year. So far, he has gotten significant put aways with all four pitches this season, with the fastball leading the charge at 21.6 percent and the changeup, curveball and slider checking in at 11.1, 9.5 and 13.6 percent respectively.
His ability to land strikes with all his pitches is a big advantage, and one or two of them taking a jump would be huge for his development.
The advanced metrics do not favor Kirby, predicting regression to come. His ability to command the strike zone and force batters to put the ball in play gives him a chance every night, and it gives the Mariners a chance to play defense behind him.
With continued growth and development, Kirby can easily follow the trail that Gilbert blazed. Taking a look at Baseball Savant’s comparable players based on velocity and movement, 2022 Logan Gilbert is his third-closest comp behind Brandon Woodruff and Dean Kremer.
Kirby has blasted past the expectation of a rookie starter already. His growth this season has been evident, and he's seamlessly stepped in for a team that desperately needed a fifth starter. There is a lot to look forward to in Seattle’s rotation for years to come and the 24-year old rookie is right in the middle of it.
