Seattle Mariners pitcher Luis Castillo throws during a game against the Los Angeles Angels on June 7 at Angel Stadium. Kirby Lee-Imagn Images

Who is Pitching For the Seattle Mariners in Upcoming Series vs. Guardians?

Originally posted on Seattle Mariners on SI
By Teren Kowatsch | Last updated Jun 13, 2025 4:00 PM ET

The Seattle Mariners will look to break their three-series losing streak and earn some crucial ground in the American League Wild Card race in their upcoming series against the Cleveland Guardians.

The Mariners will return home for the first of a three-game set against the Guardians at 7:10 p.m. PT on Friday. Seattle went 1-5 on its previous road trip and was swept for the second time in three series to end the trip.

A series win against the Guardians wouldn't just snap the Mariners' current skid, it could also pay huge dividends at the end of the season for potential tiebreakers in the AL Wild Card race.

Here's the probable pitchers for the series between Seattle and Cleveland:

*Note: Probable pitchers are subject to change

Friday, June 13 — Luis Castillo (Seattle) vs. Gavin Williams (Cleveland)

Luis Castillo saw his streak of four quality starts snapped in his last outing against the Los Angeles Angels on June 7. His strikeout numbers were consistent with his four prior starts (five), but he allowed six runs (four earned) on eight hits (three home runs). Castillo allowed three homers in April and May combined.

Luis Castillo's 2Ks in the 1st. pic.twitter.com/NRRtQkkIS3
— Rob Friedman (@PitchingNinja) June 8, 2025

Gavin Williams hasn't had the cleanest outings recently, but has been stellar with two consecutive quality starts. In his last start against the Houston Astros on June 7, Williams fanned five batters in six innings. He walked two and allowed three earned runs on five hits (one home run).

Saturday, June 14 — George Kirby (Seattle) vs. Tanner Bibee (Cleveland)

George Kirby is coming off the best showing for a Mariners starting pitcher this season. He pitched seven innings against Los Angeles on June 8. He punched out 14 batters (tied for the most in a single game in the majors this season) and allowed two earned runs on two hits (one home run).

George Kirby...13th K pic.twitter.com/Gf4tIVhK0J
— Rob Friedman (@PitchingNinja) June 8, 2025

Tanner Bibee has thrown 6.1 innings in two consecutive starts against the New York Yankees on June 3 and Houston on June 8. During that stretch, he's struck out 12 combined batters, walked two and has allowed five earned runs on nine hits (two home runs).

Sunday, June 15 — Emerson Hancock (Seattle) vs. Luis Ortiz (Cleveland)

Emerson Hancock is coming off his fourth consecutive start where he's allowed three earned runs or less. He's only allowed more than three runs once in his last 10 starts. He threw five innings against the Arizona Diamondbacks on June 9, fanned three, walked three and allowed two earned runs on six hits (one home run).

Emerson Hancock, K'ing the Side in the 4th. pic.twitter.com/jNcFhFZTNz
— Rob Friedman (@PitchingNinja) June 5, 2025

Luis Ortiz is coming off his shortest outing since April 23. He pitched 4.2 innings against the Cincinnati Reds on June 9. He struck out five, walked one and allowed four earned runs on nine hits (two home runs).

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

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