Mariners Face Do-or-Die Sunday at T-Mobile Park: Can They Stop Kansas City's Sweep?

The Mariners are in a must-win spot. Down 2-0 in the series after losses on Friday and Saturday, Seattle heads into Sunday's 4:10 p.m. first pitch knowing that another loss sends Kansas City out of T-Mobile Park with a clean sweep. For a team sitting at 16-18 overall and 10-9 at home, that's the kind of gut punch that can derail momentum fast.

The Pitching Matchup: One Ace, One Question Mark

Luis Castillo gets the ball for the Mariners on Sunday, but the 2026 season hasn't been kind to him yet. He's 0-2 with a 6.35 ERA and a 1.73 WHIP through his starts, striking out 26 batters. The Royals will counter with Kris Bubic, who's been solid at 2-1 with a 3.74 ERA and a 1.19 WHIP, with 35 strikeouts on the year.

On paper, this looks like it could be closer than the scoreboard suggests. The Mariners' pitching staff as a whole ranks sixth in baseball with a 3.69 ERA, which is something to build on. But if Castillo can't find his command and the Royals keep pounding the zone, Seattle's bullpen could get torched early.

The Bats Have to Show Up

Randy Arozarena leads the way for the Mariners with a .281 average, nine doubles, a triple, three home runs, and 16 walks. Julio Rodriguez has been heating up too, going 16 for 44 with three home runs and nine RBI over the last 10 games. The Mariners are 6-4 over their last 10, with a .262 batting average and a 4.50 ERA.

The issue? The Royals have been absolutely dominant lately. They're 7-3 in their last 10 games with a .278 average and a 4.35 ERA, outscoring opponents by 14 runs in that stretch. Kansas City sits at 14-19 overall and 5-12 on the road, but they've been money over these past two weeks.

First pitch Sunday is 4:10 p.m. EDT at T-Mobile Park. The Mariners' season just got a lot more interesting.

This article was created with AI assistance and reviewed by Seattle On Tap editorial staff. Always verify information with official team sources.