Detroit Tigers outfielder Kerry Carpenter remains on track with his rehabilitation schedule in return from a lumbar spine stress fracture, but he's frustrated watching his teammates struggle on offense without being able to help.

Carpenter is an irreplaceable slugger in the middle of the Tigers lineup, and the offense isn't the same without him.

"I'm losing it," said Carpenter with a smile. "It's been tough to watch and not be out there, especially because it's been so much fun when they're at home, I get to at least hang out with them. It's kind of tough when they're on the road."

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The good news: Carpenter is scheduled to begin baseball activities Monday following four weeks of physical therapy, exercises and rest. The 26-year-old needs about 1½ weeks of baseball activities before rehab assignment games, meaning he might not return to the Tigers until the end of July.

Carpenter, a left-handed hitter, was hitting .283 with eight home runs, 11 walks and 38 strikeouts across 50 games, posting a .914 OPS, before landing on the injured list May 29 with the lower back injury. He had a 1.004 OPS against right-handed pitchers.

The Tigers have played 21 games without Carpenter.

The Tigers hit .236 with a .684 OPS when Carpenter was healthy, but since his placement on the injured list, the Tigers are hitting .217 with a .628 OPS. (Players not named Riley Greene are hitting .204 with a .579 OPS in the 21-game stretch.)

The last four weeks have set the foundation for a full recovery.

"A bunch of treatment, a bunch of exercises, more treatment, more exercises, and then rest," Carpenter said. "That's about it until baseball starts again."

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Baseball activities begin Monday.

"Now, that could mean a lot of different things," manager A.J. Hinch said, "and it could be a slow ramp for him, but that's encouraging that he can start to do baseball things a little bit and hopefully continue to maintain his progress."

Javier Báez stays in Lakeland

Shortstop Javier Báez (lumbar spine inflammation) has been cleared for baseball activities for three days, but he hasn't reported to Comerica Park in Detroit.

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Instead, Báez is doing his work in the Tampa, Florida, area with some visits to Lakeland, home of the Tigers' spring training facility. He hit at a facility in Tampa on Friday, and he is scheduled to report to Lakeland again on Saturday.

It's unclear when Báez will show up in Detroit.

"I believe he's going to go there (to Lakeland) tomorrow, run some bases, do defense and continue his baseball progression," Hinch said. "Right now, the plan over the weekend is for him to do all of that in Lakeland."

Báez hasn't played for the Tigers since June 8.

Alex Faedo's rehab assignment

Right-handed reliever Alex Faedo (right hip inflammation) began his rehab assignment with Triple-A Toledo, completing one inning Wednesday. He is scheduled to pitch again Saturday, but that could be his final rehab outing.

He threw 21 pitches in Wednesday's appearance.

"He was a little rusty in his first outing," Hinch said, "and to simulate what he's going to be asked to do when he comes back, the one-plus to two (innings) is necessary."

After Saturday's appearance, the Tigers will evaluate whether or not to activate Faedo for Monday's series opener against the Philadelphia Phillies at Comerica Park.

"We've missed him," Hinch said. "We've got capable guys, but we consider him a weapon. He's someone who comes in at the most stressful times but also can take down a lot of outs to help bridge towards the back end of the bullpen."

Contact Evan Petzold at epetzold@freepress.com or follow him @EvanPetzold.

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This article originally appeared on Detroit Free Press: Detroit Tigers' Kerry Carpenter cleared for baseball activities