Seattle Mariners pitcher George Kirby struggles to control runners on base

Seattle Mariners starter George Kirby has become the team's most susceptible pitcher regarding the stolen base. Statcast data lists Kirby with a -5 Net Bases Prevented rating, placing him in the bottom 5% of MLB this season. Although Kirby maintains a quick pitch tempo, analysts attribute his defensive struggle to a large leg kick in his delivery. This inability to prevent runners from advancing has impacted Seattle's performance in close games, including a loss against the Oakland Athletics where stolen bases facilitated multiple runs. The increased number of baserunners allowed by Kirby, combined with his declining strikeout rate, has exacerbated the issue. While teammate Logan Gilbert has reversed his trend to become the staff's most effective pitcher at holding runners, Kirby faces a technical ceiling due to his current mechanics.

• 11:17 PMYahoo Sports — George Kirby is letting hitters run wild