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Seattle Mariners

Mariners spring training preview: Gregory Santos trade gives M’s wealth of options to close games

Seattle have another late-inning pitching option in newcomer Gregory Santos.  (Tribune News Service)
By Adam Jude Seattle Times

Best bullpen in baseball?

The Seattle Mariners had the kind of resume to stake that claim in 2023. They were, at minimum, on the fringe of that discussion in 2021 and ’22, too.

Which is to say, the Mariners have reason to feel confident about the wealth of arms they’ve assembled in their 2024 bullpen. They’ve proven they know how to get the most out of their relief pitchers.

In 2023, the Mariners’ 3.48 earned-run average ranked No. 4 among all MLB bullpens and their 26.1% strikeout rate ranked No. 2. They now return four of their most reliable relievers – Andres Muñoz, Matt Brash, Gabe Speier and Tayler Saucedo – while adding the electric right arm of 24-year-old Gregory Santos as another late-inning option.

Our spring training position preview series concludes with a look at the Mariners’ bullpen.

Who’s back

The Mariners haven’t had a designated closer since 2018, when Edwin Diaz set the franchise record with 57 saves.

Paul Sewald emerged as the de facto closer the past two seasons before he was shipped to the Diamondbacks in a trade-deadline deal last summer.

Manager Scott Servais has preferred to mix-and-match his late-inning relievers based on leverage situations, and Muñoz, Brash and Santos are all viable options to close in any given game.

Servais has hinted he might be open this year to giving one reliever the bulk of the ninth-inning duties – it could allow him to be more protective of someone like Muñoz, who battled injuries last season – but it’s unlikely Servais will name a single closer, at least not early in the season.

Muñoz, recovering from foot surgery last offseason, spent two months on the injured list early last season because of a right shoulder strain, and even after he returned he was never fully healthy. He did convert 11 of his 13 save opportunities after Sewald was traded.

Brash appeared in 78 games last season, most among all MLB relievers, and struck out 107 in 70⅔ innings. In Muñoz, Brash and Santos, the Mariners have three of the most unhittable sliders in the game.

Speier emerged as the top left-hander out of Seattle’s bullpen, striking out 64 in 54⅔ innings, and he ranked among MLB’s best relievers in chase rate (39.7%) and ground-ball rate (55.8%).

Saucedo, the lefty out of Tahoma High School, had the best season of his career, posting a 58.5% ground-ball rate with a 3.59 ERA in 52 games.

Trent Thornton, acquired in a minor trade from Toronto in late July, had a strong finish with the Mariners, with a 2.08 ERA in 26 innings. He’s expected to be stretched out this spring to serve in a potential multi-inning swingman role.

New faces

As a rookie with the White Sox last season, Santos threw a slider that ranked among the best pitches in baseball. The slider had an average speed of 91.4 mph, and Santos induced a swing-and-miss rate of 37.5%.

He threw his slider 52.6% of the time, and batters managed to hit .196 against his slider with only one extra-base hit – a double – in 156 plate appearances. (Yeah, that’s pretty good.)

The one concern: Santos finished the 2023 season on the injured list with elbow inflammation. The Mariners plan to ease him into things during spring training in hopes he’ll be ready to go on opening day.

Last month, the Mariners signed 31-year-old right-hander Austin Voth to a one-year deal. The former UW pitcher is expected to be stretched out this spring to work as rotation depth.

The Mariners added several other intriguing power arms who will compete for the eighth and final bullpen job.

Carlos Vargas, part of the return from Arizona in the Eugenio Suarez trade, had a top-10 fastball last season, averaging 99.4 mph and topping out at 101.3 mph. The 24-year-old spent most of 2023 in Triple-A, where he had a strong ground-ball rate (59%) but unimpressive surface-level stats (7.02 ERA and a 15.1% walk rate).

Jackson Kowar, a former first-round pick, came over from Atlanta in the Jarred Kelenic trade. Kowar, 27, has an upper-90s fastball but has struggled to stick in the majors; he had a 6.43 ERA last season for Atlanta, with 29 strikeouts and 20 walks in 28 innings.

The Mariners claimed right-hander Mauricio Llovera, 27, off waivers from Boston last month. He’s a sinker-baller whose pitch profile could fit well at T-Mobile Park.

Eduard Bazardo pitched well for the Mariners down the stretch and could be a factor at some point later this season.

Ty Adcock made his major-league debut for the Mariners in June. He appeared in 12 games before being optioned back to Class AA Arkansas in July. He’ll join the competition for one of the final bullpen spots this spring.

Trending up

The Mariners have a strong recent track record of turning retread relievers into productive pitchers – from Sewald, Casey Sadler and Drew Steckenrider in 2021 to Penn Murfee and Matt Festa in 2022 to Justin Topa, Speier and Saucedo last season.

The Mariners are banking on one of the newcomers – Vargas, Kowar or Llovera, perhaps – to join that list as the next out-of-nowhere success story.

Trending down

Muñoz was one of the most effective relievers in the majors in 2022, with an average fastball of 100.2 mph and a strikeout rate of 38.7%.

In 2023, he lost a full tick off his four-seam fastball (down to 99.2 mph), and his walk rate spiked considerably, up from 6.0% in 2022 to 10.4%.

By the numbers

48.5: Brash threw 659 sliders last season and induced a swing-and-miss on 48.5% of them. Batters hit just .162 against his slider, and 71 of his 107 strikeouts came with the slider.

78.2: Speier led all MLB pitchers with a 78.2% first-pitch strike rate in 2023, helping the Mariners set an MLB record in first-pitch strike rate (64.5%).