Ranking the Red Sox's options at first base: Devers back in the infield? A prospect moving positions?

The Boston Red Sox front office dreamed that this would be the year that Triston Casas would fully blossom, mashing 30 homers and fully exploiting Fenway Park's dimensions in a way that other left-handed hitters have. But Casas is out for the year after rupturing his left patellar tendon -- and now manager Alex Cora must find a replacement.

But this is not a situation in which the Red Sox have to scramble for help outside the organization. Evaluators with other teams scan Boston's big league roster and organizational depth and believe the Red Sox are in a strong position, with a lot of options.

Based on feedback from front office-types, scouts and major league staffers, here are the best first-base options for the Red Sox, in order of collective preference of those we spoke to.

1. Rafael Devers

As of Tuesday afternoon, Cora said he hadn't asked Devers about a move to first, and some rival evaluators believe that makes sense due to the political complications. After Devers was surprised by the late-winter signing of Alex Bregman and initially rejected the idea of moving from third base, Devers eventually went along with a shift to designated hitter.

"He already made one big change, so it'd be tough to ask him to do another in-season," one evaluator said. "Leave him at DH and let him get comfortable there."

Said another: "He's gone all-in at designated hitter."

But that doesn't preclude Devers from knocking on Cora's door and telling his manager he would like to move, which could be the best-case scenario for the Red Sox. And in doing this, Devers could be embracing the inevitable -- because eventually, he's probably going to move to first base. Devers is in the third year of a 10-year, $313.5 million contract that runs through 2033.

"Are you ever going to move him back to third base after getting him off that spot?" one rival official asked rhetorically. "And he's too young [28] to be settling into a full-time DH role. It's better for him if you get him out in the field."

It doesn't have to happen all at once. If Devers volunteers, he could start taking ground balls for a week or two and then gradually play at first, getting back into the kind of shape necessary to play in the field regularly.

There would be natural concerns about his defense at a new position, but a couple of evaluators noted that Devers' primary defensive problem at third base was in throwing, something he would do far less at first. At the very least, Devers would be wholly accustomed to the speed of the game for a corner infielder.

"I don't think he would be bad over there," one evaluator said. "It's not like he was a total zero at third base. He was OK at times."

If Devers were to play first, that would open the DH spot for Cora to use as a resting spot for position players dealing with weariness or nagging injuries and creating an opening for Roman Anthony or Marcelo Mayer to be promoted.

2. Marcelo Mayer

His future with the Red Sox is as a middle infielder, but there is precedent in Boston's history of using a star prospect as a stop-gap solution. In 2013, the Red Sox needed a third baseman and promoted shortstop Xander Bogaerts to play the spot, and they went on to win the World Series. For Mayer to move from shortstop to first base would be a more dramatic change, but one staffer believes he could do this with relative ease.

"He's athletic enough to do it," the staffer said, "and he'd hold down the position offensively. You'd have some growing pains on defense, but he's played on the right side of the infield before [at second] and he would hit enough to make it work.

"That's the thing -- they need offense from that position. If they weren't trying to win, you wouldn't think about it. But they are trying to win and it's something you consider."

Mayer is currently playing for Triple-A Worcester, though Red Sox fans are eager to see him with the major league team.

"It'd work for [Mayer] because it would get him to the big leagues right away," the staffer concluded.

3. Give Romy Gonzalez and Abraham Toro a full shot to share the first base job

Gonzalez and Toro have been the two players to get reps at first base since Casas went down Friday night, with Gonzalez owning the biggest share of those -- though, he exited Wednesday night's win and is day-to-day after colliding with Texas Rangers first baseman Josh Smith while trying to beat out an infield hit.

Gonzalez is a right-handed hitter who's been a good player for the Red Sox over the past two seasons and is batting .308 in 58 plate appearances this season. The utilityman had played only 20 games at first base at the big league level coming into this season, so the best that Cora could hope for would probably be league average defense. Gonzalez doesn't hit for much power, but he will get on base regularly, if he can stay healthy. Toro is a switch-hitter who has played 368 games with five different teams, generating a career adjusted OPS+ of 80.

However, it seems more likely the Red Sox look for more thump at what is a power position.

4. Move Kristian Campbell from second base to first, with Marcelo Mayer getting a shot to win the second base job

Campbell is seen by one scout as "primarily an offensive player."

"He's going to hit," the scout said. "He's not especially good at any one spot defensively. He's moved around a lot in his career, and he'd be fine at first."

Campbell has played the infield plenty in his time in baseball, and at 6-foot-3 and 200 pounds, he would present a good target for other infielders at first. And Mayer did have a brief audition at second base in spring training.

However, one evaluator said that Campbell has already been learning one new position this season and asking him to learn another could be too much -- and the Red Sox might be better just leaving him at second and allowing him to get comfortable at the plate.

5. Move Trevor Story to first base and promote Mayer to play shortstop

This was raised by ESPN analyst Eduardo Perez on the "Baseball Tonight" podcast. But as difficult as it was to ask Devers to move off third base, it might be even more complicated getting Story to buy into the idea of moving to first. He's under contract for two more seasons after this year at $25 million annually, and he's been a shortstop for almost all of his 10-year career.

Additionally: If the Red Sox are going to affect a major change, they'll do it to enhance their offense -- and Story hasn't been a big run-producer. Over 105 games in the past three seasons, he's slashing .233/.287/.354.

6. Move one of the outfielders to first -- either Wilyer Abreu or rising star prospect Roman Anthony

Some rival evaluators believe this is the worst possible option because you would be asking two high-end outfielders to learn to play infield on the fly.

"What a waste that would be," one scout said. "Anthony is going to be a star -- a guy who hits .280 with 28-30 homers, and he can really play the outfield. A total waste. They've got enough guys in the infield to move somebody else there."

7. Vaughn Grissom

The infielder acquired in the trade of Chris Sale to the Atlanta Braves, Grissom was hurt much of last year, batting .191 in 31 games for the Red Sox. In Triple-A this season, he's hitting a respectable .260/.343/.398. But two evaluators with other teams believe that there wouldn't be much of a difference between the Gonzalez/Toro platoon and what Grissom could provide offensively.

"They'd probably just go with the guys who are in the big leagues already," one staffer said.