Triston Casas’ season is almost certainly over.

The Red Sox placed their first baseman on the 15-day injured list on Saturday, and in the coming days he’ll undergo surgery to repair the left patellar tendon rupture he suffered during Friday’s game. Before Saturday afternoon’s contest, chief baseball officer Craig Breslow announced that the Sox “don’t anticipate” Casas playing again this year.

“Seems like these injuries, they pop up in kind of unconventional ways, and unfortunately this is a serious one. It’s going to keep him out for a long time,” Breslow said. (New York Mets closer Edwin Diaz missed the 2023 season after he suffered the same injury during the World Baseball Classic that March.)

Manager Alex Cora confirmed as much shortly thereafter, saying, “Hopefully, get him back stronger than ever and ready to go next year.”

Saturday is only Game No. 35 for the Red Sox. That’s a long time to be without Casas, especially for an organization with considerable depth at nearly every position but first base. In what Breslow described as the “short-term,” they brought Abraham Toro up from Triple-A Worcester.

Toro, 28, has played 365 career games in the Majors over the last six seasons — including with Alex Bregman on the ‘19-20 Houston Astros — but has only made 15 career appearances at first base. He’ll move around and play against “certain righties” while Romy Gonzalez also gets “some at-bats,” said Cora.

“Conversations about longer-term solutions are ongoing,” Breslow said. “We’ll figure out something. We’ve got no choice.”

While the chief baseball officer said they’re exploring all options, they’re likely to rule out some avenues. Namely top prospects Marcelo Mayer and Roman Anthony.

“It doesn’t seem like that’s in the plans,” Breslow said about his top shortstop and outfield prospects. “Given, I think, the bright futures that they have ahead of them at their respective positions, introducing additional variables doesn’t make sense.”

Down in Triple-A Worcester, middle infielder Vaughn Grissom has played parts of four games at first base in Triple-A, and entered Saturday hitting .287 with 31 hits, eight doubles, three homers, 11 walks, and 26 strikeouts in 28 games. Toro’s lefty bat gave him the advantage over the righty Grissom, Cora said.

Breslow didn’t explicitly rule out trying Rafael Devers at first, but he pushed back against the notion that doing so would reopen the designated-hitter role for Masataka Yoshida, who continues to rehab after offseason shoulder surgery. Yoshida was rehabbing at the team’s Fort Myers, Fla. complex, but returned to Boston for imaging after experiencing discomfort. According to Breslow, the tests didn’t show any structural issues.

“I think it’s important to decouple those things just given that Masa, he’s had some hurdles as it relates to recovering with the throwing,” said Breslow, “and we still feel like he’s a capable outfielder and want to make sure that when he comes back, he’s completely healthy. So I would try to keep those two things separate.”

After signing Bregman and moving Devers from third base to designated hitter at the end of spring training, Cora made his feelings clear. Asked if the situation is delicate, given Devers’ initial resistance to moving off third and the fact that he still takes grounders before games, he was adamant.

“From my end, right now? No. We asked him to do something in spring training. In the beginning he didn’t agree with it, and now he’s very comfortable doing what he’s doing,” said the Sox skipper. “We made a decision, we talked to him, he’s the DH. It’s not delicate at all.”

Cora also doesn’t want Connor Wong playing first, despite using the catcher there in the past. In general, he hopes to avoid moving players from their natural positions.

“His off-days are his off-days,” the Sox skipper said. “I think we pushed him because we needed to (with) the personnel that we had. So, we got two capable guys at first base, we got two capable guys behind the plate, and we can avoid that, too.”

“We’ll see where we’re at but I think Romy and Toro, they can do the job. I truly believe that,” the manager said. “We’ve been through that act before, moving people around, playing guys at first base that they never played first base, and it wasn’t good. The effort was there. (I) appreciated Franchy (Cordero) playing first, but he wasn’t a first baseman. Kyle (Schwarber), of course, we needed to play first, but he wasn’t a first baseman.

“These two guys are capable of doing it. I feel very comfortable with them. Obviously the lineup, we have to mix-and-match and find spots for them that we can maximize the lineup, but I feel very comfortable with Romy and Toro playing first.”

Regardless, Casas’ injury is a brutal blow for him and the team, and it’s especially unfortunate because a late-April rib cartilage injury cost him most of last season.

“It’s tough,” said Breslow. “You feel for Triston, given what he’s been through the last few years.”

“I talked to him last night,” Cora said. “First thing he said (was) ‘Great game.’ I was like, ‘Save it, don’t even.’ ”

“He loves baseball,” the manager continued. “This is what makes him feel comfortable. And right now, he’s not going to have it for a while.”

Other injury updates

Kristian Campbell will “most likely” be back in the lineup on Sunday after missing three games due to rib discomfort, Cora announced before Saturday’s game.

Richard Fitts is playing catch. Cora wasn’t sure if the righty would be ready to throw a bullpen this week, but said, “the progress has been great. He feels like he’s getting stronger each day.”