Sep 1, 2025; Tampa, Florida, USA; Seattle Mariners starting pitcher Luis Castillo (58) throws a pitch against the Tampa Bay Rays in the second inning at George M. Steinbrenner Field. Mandatory Credit: Nathan Ray Seebeck-Imagn Images Nathan Ray Seebeck-Imagn Images

Mariners Star Potentially At Risk Of Missing Postseason Roster

Originally posted on Fastball on SI | By Zach Pressnell | Last updated Sep 10, 2025 5:30 PM ET

The Seattle Mariners are looking to hold onto the final wild-card spot in the American League. They've struggled for weeks after the trade deadline, despite adding on in a big way, but the lineup is beginning to hit its stride again.

Seattle will need to continue to get better as the season comes to an end, but it's still the Mariners' wild-card spot to lose. If they can clinch the postseason, they'll need to make some very tough roster decisions over the next few weeks, specifically with their potential postseason roster.

FanSided's Chris Landers recently suggested that starting pitcher Luis Castillo could be at risk of missing the postseason roster this season. Castillo has been a staple in the Mariners' rotation for the last few years, but he's at risk of missing the postseason roster now.

Starting pitcher Luis Castillo could miss Mariners' postseason roster

"This one hurts, I'll admit. Castillo has been a stalwart for Seattle for years now, and with the team finally on the precipice of returning to the playoffs, would the Mariners really leave him out in the cold? Unfortunately, they might not have a choice: You only need three starters for a Wild Card series, and right now Logan Gilbert, Bryan Woo and George Kirby are the obvious choices. Heck, even Bryce Miller is probably ahead of Castillo given how badly the latter has struggled of late. And he doesn't figure to profile well in a move to the bullpen, meaning he could be out of luck."

Castillo has been a consistent staple in the Mariners' rotation for years, but the team likely only needs three starting pitchers for the wild-card round and division series. Castillo is likely the No. 4 starter in Seattle, though the pitching staff hasn't been that dominant this season.

While his production has been fine, the underlying metrics indicate he's heading into a decline. The righty's fastball is losing velocity and movement with each year. He's not striking out as many hitters as many are used to. There's a real chance he'll miss the wild-card roster and potentially beyond, if the Mariners make it.

More MLB: Marlins Hit Jackpot With Luis Arraez Trade; Young Star Turning Heads

This article first appeared on Fastball on SI and was syndicated with permission.

More must-reads: