MIAMI -- Some core Marlins currently on the disabled list are getting closer to returning. Left fielder Christian Yelich and right-hander Henderson Alvarez are expected back in the not-too-distant future.

Yelich (lower back strain) is expected to play in a rehab assignment game at Class A Jupiter on Sunday. Alvarez (right shoulder inflammation) could be back in the middle of May.

"Yelich is hitting and running, and on Sunday, he will start playing," manager Mike Redmond said. "Henderson will throw another bullpen [session on Saturday]. If things go well, we'll develop a program, and he will likely make a start in the Minor Leagues."

Alvarez went on the disabled list on April 13. The right-hander is expected to appear in an extended spring game against Minor Leaguers in Jupiter, Fla., on Thursday. A potential return to the rotation could come May 17 against the Braves at Marlins Park.

"It's looking good," Redmond said of Alvarez. "He says he feels great. His arm feels good. He's progressing as well. Knowing that he's not far off is good."

Video: [email protected]: Alvarez pitches seven solid in tough loss

Alvarez, the Opening Day starter, felt discomfort during an April 12 loss to the Rays in Miami.

The Marlins are aiming for their pitching depth to hold the rotation together until Alvarez and Jose Fernandez return in the upcoming weeks. Fernandez, recovering from Tommy John surgery, faced batters for the first time on Thursday in Jupiter. The right-hander is next slated to see hitters on Monday. Fernandez's window to return is mid-June to mid-July.

"With Jose, everything went well," Redmond said. "He pitched great."

Yelich most recently played on April 19 vs. the Mets. The left fielder is eligible to be reinstated as early as Wednesday, when the team is at Washington.

Chances are Yelich will be ready that day, or perhaps the next, when the team opens a four-game set at San Francisco.

Catcher Jeff Mathis (broken right hand) and infielder Don Kelly (fractured right ring finger) each have been cleared to resume baseball activities. Both were examined by a hand specialist, and they were given the green light to begin hitting and throwing.

"Good news on that front, they're healing up and feeling much better," Redmond said.