Seattle Mariners Pitcher George Kirby Struggles Amid Velocity Drop

Seattle Mariners right-handed starting pitcher George Kirby saw his season record drop to 8-10 with a 4.18 ERA after giving up six runs over 3 1/3 innings against the Milwaukee Brewers on August 20, 2026.

The outing in Milwaukee marked Kirby's second straight difficult start over a six-day stretch. He surrendered nine hits, issued two walks, committed two pitch clock violations, and registered his lowest pitch velocity of the season during the appearance.

Troubles for the 28-year-old starter began earlier in the month during an August 14 matchup against the Houston Astros at Daikin Park. Houston shelled Kirby for five earned runs across 4 2/3 innings, cutting short a brief turnaround where he had previously tossed seven shutout innings on August 2 and allowed one run on August 8.

Statistics reveal a broader trend of diminishing dominance inside the strike zone. Kirby's strikeout rate has dropped from 26.1 percent in 2025 to 19.9 percent in 2026, while his whiff rate sits at 21.6 percent, below the league average of 25 percent.

Despite maintaining a low 5.6 percent walk rate, opposing batters are hitting .285 against Kirby, which represents the highest batting average allowed by any qualified pitcher in Major League Baseball. When hitters swing at his pitches inside the zone, they make contact 86.9 percent of the time.

Underlying metrics indicate some bad luck, as Kirby's expected batting average of .260 and expected ERA of 4.00 both sit below his actual numbers. However, his recent physical performance and declining numbers pose potential challenges for Seattle's front office ahead of the upcoming offseason.

Kirby will make his next scheduled start against the Philadelphia Phillies as he seeks to regain control on the mound.