Seattle Mariners probable pitchers & starting lineups vs. San Francisco Giants, April 4

After opening with a seven-game homestand that resulted in a disappointing 3-4 record, the Seattle Mariners are hitting the road for the first time in their 2025 season.

It's only a three-game road trip, and not even that far out of the way. The Mariners are taking on the San Francisco Giants at Oracle Park for a three-game set over the weekend, starting with a matinee for the Giants' home opener on Friday. First pitch is scheduled for 1:35 p.m. PT.

An interesting pitching matchup is on tap for Game 1. The Mariners are starting a right-hander with a familiar name, but no career major league starts. The Giants are countering with a righty whose accolades include nine All-Star selections, three Cy Young Awards, and an MVP.

Here's more on that matchup, plus the likely starting lineups and how to tune in.

Starting Pitchers

For the Mariners: Luis F. Castillo, RHP (0-0)

The Mariners are starting a Luis Castillo for the second game in a row, but not the Luis Castillo. This is the other one, commonly referred to as Luis F. Castillo.

This Castillo is a 30-year-old righty who made three relief appearances for the Detroit Tigers in 2022, and then went overseas to pitch in Japan for a couple seasons. He posted a 3.01 ERA in 27 games across 2023 and 2024, parlaying that success into a minor league deal with Seattle.

He got his fastball up to 95.1 mph in spring training. And much like the Mariners' other Luis Castillo sometimes does, he got Rob "Pitching Ninja" Friedman's attention with a changeup.

For the Giants: Justin Verlander, RHP (0-0)

Verlander should need no introduction. The 42-year-old has been pitching in the majors since 2005, and his ticket to the Hall of Fame has been punched for a while now.

As for what he still has left at his age — not to mention in his 20th season — the answer may be "plenty." Verlander sat at 94.1 mph with his fastball in his Giants debut on March 29, a 0.6 mph increase over 2024. He went five innings and allowed two runs, striking out five and walking only one.

Verlander is a familiar foe to Mariners fans. He's made 39 starts against Seattle for his career, and those have yielded a 2.98 ERA with 275 strikeouts in 260 innings.

Mariners Starting Lineup vs. Verlander

1. RF Victor Robles (R)
2. CF Julio Rodríguez (R)
3. C Cal Raleigh (S)
4. LF Randy Arozarena (R)
5. 3B Jorge Polanco (S)
6. DH Luke Raley (L)
7. DH Rowdy Tellez (L)
8. 1B Ryan Bliss (R)
9. SS J.P. Crawford (L)

Giants Starting Lineup vs. Castillo

1. 1B LaMonte Wade Jr. (L)
2. SS Willy Adames (R)
3. CF Jung Hoo Lee (L)
4. 3B Matt Chapman (R)
5. LF Heliot Ramos (R)
6. RF Mike Yastrzemski (L)
7. DH Wilmer Flores (R)
8. C Patrick Bailey (S)
9. 2B Tyler Fitzgerald (R)

How can I watch the Mariners today?

Regional Coverage

• Washington, Oregon, Idaho, Montana, Alaska: The game will be televised on ROOT Sports Northwest.​
• Northern and Central California, Southern Oregon, Nevada, Hawaii: The game will be televised on NBC Sports Bay Area.

Satellite Coverage

• Nationwide: Available via DirectTV.

Radio Broadcast

• Seattle Region: Tune in to Seattle Sports 710 AM or stream the audio live at seattlesports.com.​
• Bay Area and Other Regions: Tune in to KNBR 680 and other options.

Streaming Options

• ROOT Sports Streaming App: Fans in Washington, Oregon, Idaho, Montana, and Alaska can stream the game live through the ROOT Sports streaming service
• FuboTV: Subscribers in the aforementioned regions can also stream the game live via FuboTV, which carries ROOT Sports Northwest.
• MLB.TV: Out-of-market viewers can watch the game live with an MLB.TV (subscription required). Giants fans also have Giants.TV as an option.

What's at Stake?

The Mariners aren't going to return to the playoffs for the first time since 2022 if they finish below .500. The goal for Friday is to win the game and get to 4-4, and then go from there.

More specifically, there continues to be anxiety surrounding the offense. The Mariners have just 18 runs to show for their first seven games, and their starting lineup is littered with averages in the .100s and .200s. It also bears noting that Seattle is third from the bottom of MLB in hard-hit balls, though Arozarena (nine), J-Rod (eight), and Raleigh (seven) are doing OK on that front.

Otherwise, fans can only hope that the road is not as hostile to the Mariners as it was in 2024. They went 36-45 away from T-Mobile Park, which ended up being a huge factor as they fell just one game short of qualifying for a playoff spot.

For today, at least, the Mariners will see if they can get their bats going and if pitchers named Luis Castillo are the franchise's good-luck charm.