Seattle Mariners RHP Gregory Santos set to begin rehab assignment

PEORIA, ARIZONA - FEBRUARY 23: Gregory Santos of the Seattle Mariners poses for a portrait during photo day at the Peoria Sports Complex on February 23, 2024 in Peoria, Arizona.  (Steph Chambers / Getty Images)

Seattle Mariners reliever Gregory Santos will be sent out on a rehab assignment early next week after throwing a 21-pitch live batting practice session on Friday afternoon.

"The objective for me today, I think, was just to finish healthy," Santos said through interpreter Freddy Llanos. "Just throw a good live BP, go out and go to Triple-A, but the objective was to finish healthy."

Santos threw four-plus at-bats to hitters Ryan Bliss and Victor Robles during his outing, allowing a sharp base-hit to left field from Bliss, and striking out Robles once.

"I think it was enough pitches," Santos said. "At first I was having a little issue locating the fastball a little bit. The body just kind of synchronized and everything was good."

General manager Justin Hollander said that Santos will begin his rehab assignment in Triple-A with the Tacoma Rainiers on Tuesday.

"Velocity looks good. He feels good. He will start a rehab assignment on July 2 in Tacoma. We will see how it goes sort of outing to outing. We don't anticipate a very long rehab assignment because he's been growing with us, but first one will be on July 2," Hollander said.

Santos has not appeared in a game for the Mariners yet after being acquired in a trade with the Chicago White Sox in February. Santos sustained a strained lat muscle that sidelined him during spring training and he's been working his way back ever since. He spent the first month of the season doing rehab work at the team's complex in Peoriz, Ariz. before continuing his recovering path with the team in Seattle since May.

"It was a little difficult because it felt like whenever I was making progress, there would be this setback and then I'd go back. But I just got to keep my head down, work, and I knew God was going to give me the opportunity to be here with my team again," Santos said.

Santos said he felt "very good" after the outing on Friday and confirmed he feels ready for a rehab outing. Bliss also faced Santos during his prior live batting practice session in Miami on the team's recent road trip.

"It's my second time facing him. It didn't get any easier," Bliss said. "He'll be a weapon in the bullpen for a team like us and excited to get back with him."

Bliss raved about Santos' sinker as being a particularly difficult pitch to handle.

"It’s 98 with splitter movement. You just don’t see that," Bliss said. "The ball drops out of nowhere. You don’t really see it. It’s something unique, and it’s a really good pitch."

Santos had his first full season in the majors last season with the White Sox, appearing in 60 games with 66 ⅓ innings pitched. He had a 3.39 ERA with 66 strikeouts and 17 walks with two walks allowed. The Mariners traded minor league right-handed pitcher Prelander Berroa, outfielder Zach DeLoach, and a competitive balance round B draft pick.

With Matt Brash out for the season after Tommy John surgery, and left-hander Gabe Speier on the injured list with a rotator cuff strain, Santos' eventual return to the bullpen will be a welcome addition to the Mariners' roster.

"He looked great," manager Scott Servais said. "He looked really good down in Miami. I thought he threw the ball really well again today. We'll see how he feels tomorrow and then take it from there."

Hollander said that Speier will throw off a mound on Saturday and progress to a bullpen session on Tuesday. 

"He is tracking well. We anticipate right around the All-Star break, probably just after the All-Star break for Gabe," Hollander said.

Notes:

The Mariners recalled left-handed pitcher Jhonathan Díaz from Triple-A Tacoma and optioned right-handed reliever Cody Bolton to Tacoma ahead of Friday night's game with the Minnesota Twins.

Díaz is likely to make a start in the coming days for the Mariners with Bryan Woo now on the injured list due to a right hamstring strain. Woo was injured in his last start in Tampa on the team's road trip.

"He's feeling better," Hollander said of Woo. "MRI on the hamstring along with an ultrasound. Originally, it showed some mild inflammation, not a serious strain by any means. We don't anticipate a long absence. The telling point will be how soon he can get off a mound, so we'll figure that out over the next couple days how he feels, but again, we don't anticipate a long absence. It's just a matter of when he can comfortably get off the mound without favoring it or without limiting his lower body impact in his delivery."

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