Three Mariners who are making unexpected contributions

The Seattle Mariners are 8-8 through their first 16 games, but after a 3-7 start, it’s a .500 record that seemed almost unattainable before their recent 5-1 homestand began.

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Some expected faces have had big contributions early on. Cal Raleigh slugged a home run in each of the team’s victories during its sweep of Texas over the weekend. Randy Arozarena has come up in clutch moments, including a grand slam and walk-off walk in a wild comeback win over the Astros last week. Starting pitchers Logan Gilbert, Luis Castillo, Bryan Woo and Bryce Miller have all had solid outings. And closer Andrés Muñoz has been lights out at the end of games.

But contributions have also come from some unexpected players. Seattle Sports’ Brock and Salk highlighted three who have surprised thus far on Monday, with a caveat that Jorge Polanco was too obvious of a choice to include.

Miles Mastrobuoni

The Mariners traded cash for Miles Mastrobuoni back in January after he was designated for assignment by the Cubs. At the time, it appeared the left-handed-hitting utilityman was just a depth piece for a roster that largely stayed intact over the offseason.

Brock and Salk co-host Mike Salk figured switch-hitting infielder Leo Rivas would get the nod on the opening day roster instead, but Mastrobuoni earned a roster spot with a strong spring. In 35 Cactus League at-bats, he hit .428 with a 1.059 OPS and four extra-base hits.

While Mastrobuoni ended up being the final player from the opening day roster to get into a game, he’s picked up where he left on in spring and made a solid impact as a role player at the bottom of the lineup.

Mastrobuoni is hitting .318 with a .693 OPS in 22 at-bats thus far, and he came through in a big way during Seattle’s 5-1 homestand. He collected a pair of hits and scored two runs in the 7-6 comeback win over the Astros last Thursday and delivered another multi-hit game Saturday.

Perhaps the most surprising aspect is just how hard Mastrobuoni has been hitting the ball. His 94.4 mph average exit velocity and 65% hard-hit rate are among the best in the league, and his Baseball Savant page is filled with red, which is a very good thing.

“He’s hit the ball hard. He’s played good defense for a guy that was essentially a leftover, gone from the Cubs because they didn’t want him anymore,” Salk said. “… He’s had big walks and big hits in big moments. Like, where would you be right now without Miles Mastrobuoni? I can’t believe those words just came out of my mouth.”

This is all coming from a player who hit .194 in 50 MLB games last season and had a career .219/.279/.263 slash line entering 2025.

“He’s had a couple 100 at-bat (seasons) in the big leagues, not a lot of power, doesn’t profile as an every (day player),” co-host Brock Huard said. “… But as a role player, a good athlete that puts the barrel on the ball, understands what he is and what he isn’t, isn’t swinging for the fences because that’s not his game, but actually hits the ball hard. I mean, is that not like a textbook Dan Wilson, Edgar Martinez, Kevin Seitzer kind of (guy)?”

Gabe Speier

The Mariners have already seen what reliever Gabe Speier is capable of. He became a key member of the club in 2023 while providing a reliable lefty presence out the bullpen on a roster without many pitching options from the left side. But he took a major step back last season.

After surrendering only one run in 10 2/3 innings through April 2024, Speier posted a 9.69 ERA over 13 innings the rest of the way. During that time, he landed on the injured list with a left lat strain and threw more innings in Triple-A than he did the big leagues.

Speier has been lights out thus far in 2025, though. The left-hander has allowed just two hits and no walks with eight strikeouts through 6 2/3 scoreless innings. He’s struck out 36.4% of the batters he’s faced.

“I was definitely a Gabe Speier doubter,” Salk said. “I know he had a great first season here. Last year, he was injured but also bad. He’s a reliever. (They’re) up, down – you never know what you’re going to get. I would not have been surprised if Gabe Speier had given them nothing.”

“He’s been unbelievable,” Salk added. “He’s been the best pitcher in the bullpen.”

Speier’s fastball and sinker are sitting around 95 mph after dipping to 93 mph last season. He also leads the team in first-pitch strikes at 81.8%.

“He looks like the guy he was two years ago and then some because that velo is there, that command is there,” Huard said. “If you wanna throw strike one, is there not a better poster boy for strike one then Gabe Speier? I don’t think there is, and he’s been awesome.”

Carlos Vargas

There was a chance the final remaining piece of the Eugenio Suárez trade would be off the Mariners’ roster when the season began. Right-hander Carlos Vargas, who is out of minor league options, was a bubble candidate to make the opening day roster, and by doing so avoided being designated for assignment. After a rocky start, he’s been nails while providing some needed innings out of the bullpen.

Vargas, who features a sinker in the mid-to-upper 90s, is on a run of four consecutive scoreless outings out of the bullpen (each an inning apiece), including three times during Seattle’s recent homestand. He also provided some needed length when he pitched 3 2/3 innings after starter Emerson Hancock lasted just two-thirds of an inning on March 31.

In total, Vargas has a 2.79 ERA and 1.14 WHIP with seven strikeouts over a bullpen-high 9 2/3 innings pitched.

“He’s been unbelievable,” Salk said. “I mean, he didn’t look good in his first outing, and then after that, he’s looked great.”

The most encouraging sign for Vargas is that he’s walked only one batter. Control problems were a reason he spent all of last season in Triple-A.

“When you see him walk out on the mound with the height and the leg (kick), you’re like, ‘Oh, that’s a high-leverage reliever,’” Salk said. “He hasn’t been because he hasn’t had any ability to command it, but he has this year. He’s looked really good.”

Hear the full conversation at this link or in the audio player near the top of this story. Listen to Brock and Salk weekdays from 6-10 a.m. or find the podcast on the Seattle Sports app.

More on the Seattle Mariners

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• Brock and Salk: Is the Seattle Mariners’ recent offensive outburst real?
• Seattle Mariners Observations: What stands out after sweep of Rangers
• Another one: M’s now have nine prospects in Baseball America Top 100
• Seattle Mariners see a lot of promise in prospect Ben Williamson

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