MINNEAPOLIS -- The Twins’ lineup is nearly whole again.

The Twins reinstated left fielder Eddie Rosario and first baseman C.J. Cron from the 10-day injured list on Tuesday, restoring a pair of important power bats to the heart of their lineup and also adding Rosario’s rangy, aggressive defense to an outfield that had largely been in flux for the last several weeks.

In corresponding moves, Byron Buxton was placed on the 7-day injured list for concussion protocol and reliever Mike Morin was designated for assignment.

Rosario had missed 13 games with a left ankle sprain that was sustained as he rounded first base during a June 26 contest against the Rays. Though Rosario had said during the Twins' recent series in Cleveland that his ankle felt fine and his workouts had been going well, the club had opted to remain cautious with Rosario's recovery timeline.

"The last couple of days in Cleveland, I felt better," Rosario said. "I said I feel ready to play in the game. Same Eddie Rosario. I don’t want to play too much different."

Entering Tuesday, Rosario has posted what would be career bests in slugging percentage (.529) and OPS (.841) and remains second on the team with 20 homers, trailing only Max Kepler's 23 blasts.

Because Cron was placed on the injured list before the All-Star break with right thumb inflammation, he only missed five games as he rested the thumb, which had been sore throughout much of the season and had been aggravated by his continued hitting.

"When I got put on the IL, it wasn't in the best of spots," Cron said. "Pretty much any time I made contact not perfectly on the barrel, it was ringing pretty good in there. It's nice just to let it calm down a little bit, and hopefully it won't spark back up."

What's the deal with Buxton?

The 27-year-old Rosario's return to the defense in particular looms large in light of the continued absence of Buxton, who was named the Twins' 2019 Heart and Hustle Award winner by the Major League Baseball Players Alumni Association on Tuesday.

Buxton was removed from Saturday's game against the Indians after he hit his head on the ground while making a diving catch, and he underwent testing over the last several days before he was ultimately moved to the injured list.

"It's a situation where he's dealing with some symptoms, still, at this point," manager Rocco Baldelli said. "So we're not going to mess around, really, in any way. This is serious stuff, the health of Buck is obviously the most important thing. I think it's something that is already resolving itself in some ways, but something where I think this is the right move."

Buxton has already been sidelined for three days with the injury, meaning that he could be activated from the 7-day injured list as soon as Sunday. Baldelli said that Buxton has improved, but the Twins will take it easy with him and have him continue to be evaluated by doctors. They hope to have a better idea of where he's at in the coming days.

The Twins haven’t had their top four outfield options -- Rosario, Buxton, Kepler and Marwin Gonzalez -- on their active roster together since June 17. The Twins have gone 11-10 in that stretch without their full complement of outfielders, and 6-7 without Rosario.

"It's been a tough couple of weeks when it comes to injuries and things like that," Rosario said. "But I'm back today and I know what Buxton is going through is nothing bad, and he'll be back soon as well."

Why Morin? What does this mean?

Morin being designated for assignment certainly came as a surprise after the 28-year-old right-hander had posted a 3.18 ERA and a 0.97 WHIP in 23 relief appearances out of the Twins' bullpen this season. His ERA had dropped to as low as 1.66 before he allowed four earned runs in his last appearance in Oakland on July 4.

When a player's contract is designated for assignment -- often abbreviated "DFA" -- that player is immediately removed from his club's 40-man roster, and 25-man roster if he was on that as well. Within seven days of the transaction (it was previously 10 days), the player must either be traded, released or placed on irrevocable outright waivers.

"He’s gone out there and performed and gotten the job done, so to look at a guy and to have to give him that news -- a guy that’s done his job very well -- is very difficult," Baldelli said. "It’s simply a roster decision that kind of had to be made. When we’re adding guys and you start looking around for the right person [to move off the roster], there is no right person. You just have to go find what seemingly makes the most sense."

Morin's removal leaves the 40-man roster at 37 players. With the Twins' bullpen also down to seven as the team begins a stretch of 13 straight games, there will almost certainly be another reliever added to the Major League staff in the coming days.

The three openings afford the Twins an opportunity to call up a reliever who isn’t already on the 40-man roster like Cody Allen, Carlos Torres or Cody Stashak -- or, perhaps, to make acquisitions on the trade market. Allen, who was released by the Angels in June, served as the opener for Triple-A Rochester on Tuesday and has 153 career saves.

The fact that Morin was the choice appears to serve for now as an endorsement of Zack Littell and Tyler Duffey, both of whom have remaining Minor League options. But they have been moved into increasingly high-leverage roles out of the Twins' bullpen over the last several weeks and have largely responded well.