Mariners acquire reliever Santos from White Sox for 2 prospects, draft pick

Feb 3, 2024, 2:06 PM | Updated: Feb 5, 2024, 12:43 pm

Seattle Mariners Gregory Santos...

Gregory Santos of the Chicago White Sox on July 28, 2023. (Michael Reaves/Getty Images)

(Michael Reaves/Getty Images)

The Seattle Mariners gave up a trusted reliever in Justin Topa in order to help get second baseman Jorge Polanco earlier this week. But the M’s have made another deal for a reliever, and it’s someone who very well could be pitching leverage innings for Seattle in 2024.

Morosi: Trading for Polanco was move Seattle Mariners ‘had to make’

The Mariners have acquired 24-year-old right-hander Gregory Santos from the Chicago White Sox. In return, Seattle is sending young reliever Prelander Berroa, outfield prospect Zach DeLoach and the 69th overall pick in July’s MLB Draft to Chicago. Berroa is Seattle’s No. 15 prospect, per MLB Pipeline, and DeLoach is No. 25. Berroa made his MLB debut this past season.

“Gregory is coming off a season in which he established himself as one of the most exciting young relievers in MLB,” Mariners president of baseball operations Jerry Dipoto said of the deal. “His combination of high velocity, dynamic slider and groundball inducing style are all standout traits. He brings the potential for impact to a bullpen group that has been a driving force in our team’s success over the past three seasons.”

Santos made his MLB debut in April of 2021 and barely pitched that year and in 2022 at the MLB level with the San Francisco Giants. In June of 2021, Santos was suspended 80 games for testing positive for a performance-enhancing drug.

Santos became an MLB regular in 2023 with Chicago, and he put together a very, very good season. (Santos takes the hill at 2:57 in the video below.)

In 66 1/3 innings, Santos posted a 3.39 ERA, 1.296 WHIP, and 2.56 FIP while striking out 66 and walking 17.

Santos is an intriguing arm as he’s both a power arm and someone who is great at limiting hard contact.

In 2023, Santos was the best in baseball at missing barrels, ranking in the 100th percentile in that category, per Statcast, as well as 78th percentile in hard-hit rate and 87th percentile in groundball rate. Santos also averaged 98.8 mph with his fastball and allowed just two home runs on the year.

Santos also posted an elite chase rate of 33.5%, good for 91st percentile in MLB, as well as a 30% whiff rate, good for 77th percentile.

Most power arms with high-velocity fastballs come with questions about control, but Santos pounded the zone, ranking in the 85th percentile in walk rate.

Santos is effectively a two-pitch pitcher like most relievers, leaning on a sinker and slider combination.

The sinker is a hard one that helped keep the ball on the ground and the slider was one of the better pitches in baseball in 2023.

Santos’ slider, which he used more than 52% of the time, is a hard one, averaging 91.4 mph. Opponents whiffed at it over 37% of the time and also hit under .200 off of it. Of the 29 hits Santos gave up on his slider, 28 were singles and the lone extra-base hit was a double.

The Mariners’ bullpen remains headlined by Andrés Muñoz and Matt Brash, while Gabe Speier and Tayler Saucedo are also set to return after becoming key parts of Seattle’s 2023 bullpen. Santos now figures to be a key part of that ‘pen.

Santos did end the year on the injured list with right elbow inflammation, which is something to keep an eye on. According to a report from December, it was unclear if Santos will be at full strength for the start of spring training.

Mitch Garver has interesting insight on Seattle Mariners’ pitchers, trade additions

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