Inside The Mariners

Seattle Mariners Pitcher Will Make First Major League Start vs San Francisco Giants

Luis F. Castillo will make his first-ever pro start and Bryce Miller and Bryan Woo will be looking to carry the team to a series win in the Mariners first road stretch.
Teren Kowatsch|
Seattle Mariners starting pitcher Bryce Miller throws during a game against the Athletics on March 28 at T-Mobile Park.
Seattle Mariners starting pitcher Bryce Miller throws during a game against the Athletics on March 28 at T-Mobile Park. | Joe Nicholson-Imagn Images

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Seattle MarinersSan Francisco Giants

April 3, 3:48 p.m. PT: This article has been updated to show the matchups after the Seattle Mariners re-ordered the starting rotation.

The Seattle Mariners will play their first road series of the season against the San Francisco Giants beginning April 4 at 1:35 p.m. PT.

The Mariners will have a pitcher making his first major league start while facing the best pitchers the Giants have to offer.

Here's the upcoming pitching matchups for Seattle's first road series of the season:

Friday, April 4 — Luis F. Castillo (Seattle) vs. Justin Verlander (San Francisco)

Luis Castillo will start for the second game in a row for the Mariners. Or, more appropriately, a Luis Castillo. Luis M. Castillo, the three-time All-Star and two-time Seattle Opening Day starter, pitched the series finale against the Detroit Tigers on Wednesday. Luis F. Castillo will start his first major league game on Friday.

F. Castillo was originally signed by the Arizona Diamondbacks as an international free agent out of Venezuela on Feb. 16, 2012. His only bit of major league action was pitching three games in relief for (ironically) the Tigers in 2022. He had four strikeouts across 3.2 innings pitched. The Mariners signed F. Castillo to a minor league contract on Jan. 30, 2025. He's made one start this season for the Triple-A Tacoma Rainiers. He struck out two batters in 5.2 innings pitched and allowed one earned run on two hits.

F. Castillo will get the nod after Seattle optioned starter Emerson Hancock to the Rainiers on Monday.

The ageless Justin Verlander (42 years-old) will also his second start of the year coming off his own mixed showing. He pitched five innings March 29 against the Cincinnati Reds and struck out five batters. He allowed two earned runs on six hits (one home run).

F. Castillo will be looking to make a good first impression and Verlander will try to get closer to midseason form.

Saturday, April 5 — Bryce Miller (Seattle) vs. Robbie Ray (San Francisco)

Bryce Miller will still be looking for his first quality of the season Friday. Miller took the mound for the third game of the season against the Athletics. He struck out four batters in 5.2 innings pitched, walked two and allowed three earned runs on six hits (one home run). Miller's still had plus stuff in his first outing. His knuckle curve generated a 46.2% whiff rate on 19 pitches, according to Baseball Savant.

He'll face former Mariners and Cy Young-winning hurler Robbie Ray, who's looking to get back to form. Ray allowed three earned runs on three hits (two home runs) and struck out four batters in 5.1 innings pitched on Sunday. The last time he pitched against Seattle, it was Aug. 25, 2024. It was his seventh start of the year since returning from the injured list on July 24. He threw three innings before exiting the game with a left hamstring strain. He missed the rest of the year with that injury.

Sunday, April 6 — Bryan Woo (Seattle) vs. Jordan Hicks (San Francisco)

Woo put together a quality start in his first outing against the Athletics on Saturday. He fanned five batters in six innings, walked two and allowed one earned run on three hits (one home run). Woo, an Oakland, Calif., native, has had a tendency in his three-year career for pitching well against his (former) home town team. But he also does well against Bay Area teams in general.

In two starts against San Francisco, Woo has a 2.08 ERA with 14 strikeouts in 13 innings pitched.

The Mariners will have their work cut out for them against former reliever-turned-starter Jordan Hicks. The former St. Louis Cardinal is coming off a quality start where he allowed one hit and no earned run in six innings pitched. He fanned six batters in his start March 31.

A series win or sweep for Seattle will give it a .500 record or better going into its next homestead. The Mariners next stretch at T-Mobile Park will be against American League West rivals the Houston Astros and Texas Rangers beginning April 7.

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Teren Kowatsch
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