ARLINGTON, Texas — The expected roster move was made official Tuesday.

The Mariners placed designated hitter Corey Hart on the 15-day disabled list with a hamstring strain. To replace him on the 25-man roster, they recalled infielder Nick Franklin from Class AAA Tacoma.

Franklin flew to Texas on Monday, while Hart was in Seattle being examined by team doctors. After undergoing a MRI and being examined by Dr. Edward Khalfayan, Hart was diagnosed with a Grade 2 hamstring sprain.

“It’s not good,” manager Lloyd McClendon said. “He’s supposed to be out four to six weeks.”

Hart was hitting .209 (29 for 139) with five doubles, five home runs and 17 RBI.

With Logan Morrison still recovering from his own strained hamstring, McClendon doesn’t have a lot of options. He put Franklin in as the DH on Tuesday against the Rangers.

“We gotta find one,” McClendon said. “We don’t have one. Franklin’s DH’ing tonight. But I think we’d all agree he’s not a typical DH. It is what it is. We’ll make do and do the best that we can just like we did with our pitching and everything else.”

The Mariners might not have a set designated hitter for now. Instead, they will mix and match at the position using an assortment of players, including Franklin, Stefen Romero and maybe even Robinson Cano to get him some rest.

“I will talk to him and see how he’s feeling,” McClendon said of Cano. “A lot of it depends on his legs. He prefers to play the field. But it’s nice to get him in there at DH and still have his bat in the lineup.”

Franklin won’t be a permanent DH, nor will he be replacing Brad Miller as the everyday shortstop. McClendon expects to use him at multiple positions, including starts in the outfield.

“I haven’t told him anything other than stay hot and swing the bat good,” McClendon said. “There are plenty of spots for guys that are swinging the bats good. I imagine he will play some outfield, he’ll play some shortstop, he’ll DH. If Robby DHs, he may play second.”

Franklin was swinging the bat with ridiculous success for Class AAA Tacoma. He was batting .376 (41 for 109) with 21 runs scored, seven doubles, seven home runs and 26 RBI for the Rainiers.

Franklin, who had two hits Tuesday night, wasn’t too concerned about his role as long as he’s getting his at-bats.

“I’m ready to rock and roll and ready to do anything that comes my way,” he said.

Paxton, Walker throw simulated games

Taijuan Walker and James Paxton threw their simulated games. Walker threw two innings — totaling 35 pitches. Paxton threw three innings, totaling 53 pitches.

It was Paxton’s second simulated game and he will likely head out on a rehab assignment by the weekend.

“I felt good,” Paxton said. “I felt the ball was coming out better today, my change-up was better today. I was hitting my spots a little better today. I feel like it’s coming around.”

Better than his last sim game?

“It was definitely better this time,” he said. “It was a step forward with my command and making pitches. I felt like I made more pitches today than the other day.”

For Walker, it was the first time he faced a batter since being shut down during his last rehab outing with shoulder stiffness.

“I threw everything,” he said. “Everything felt good. My mechanics felt good. I felt like everything was in sync. My balance point was good.”

Ryan Divish: 206-464-2373

or rdivish@seattletimes.com