CLEVELAND -- The Tigers have a minor injury issue with Victor Martinez, but the situation could become serious by the end of the weekend if he can't catch soon. Martinez tweaked his sprained left knee running out his infield single on Wednesday, but said on Thursday that he feels OK.

Martinez was in the lineup at DH but can't play the field without risking re-injury. That wasn't an issue on Thursday, since Alex Avila was going to catch Justin Verlander anyway, but at some point this weekend in Baltimore, manager Jim Leyland would probably like to give Avila a day off.

"We're in a little bind," Leyland said. "Victor can't catch right now. That's also a day-to-day thing."

If the situation remains into next week, the Tigers might be forced to call up a catcher to back up Avila. But the only other catcher on the 40-man roster is Omir Santos, who's working his way back from a thigh injury that has sidelined him for the past month.

Santos went 0-for-2 on Thursday in a rehab start for the Tigers' Gulf Coast League team. He's scheduled to catch twice more there, Leyland said, and at that point he could rejoin Triple-A Toledo, or be an option for the Tigers if they need a second catcher.

Boesch diagnosed with sprained thumb

CLEVELAND -- Brennan Boesch was diagnosed with a second-degree sprain of his right thumb, slightly more serious than originally hoped, but both the Tigers and their left fielder believe he can be back within a few days.

Boesch visited with hand specialist Dr. Tom Graham again on Thursday morning for an MRI, which backed up the X-rays taken on Wednesday morning.

"We have to get the swelling down, [though] we didn't have a lot of swelling," Kevin Rand, head athletic trainer, said.

From there, Rand continued, the team's medical staff will work to get range of motion back in the thumb, which Boesch needs for bat control. Since the injury is to his non-throwing hand and the bottom hand of his batting grip, he can play with less range in it rather than if the sprain was his left thumb.

Boesch sounds as though he would like to push it once the swelling is down.

"It feels a lot better today, a lot less swollen, in my opinion," Boesch said. "I'm cautiously optimistic that I'll be in the lineup a lot sooner than probably the doctor I just saw would expect me to be. I talked to [manager Jim Leyland]. It's all about how it feels. It's not about what anyone says. It feels better."

Boesch wouldn't eliminate the possibility that he could play on Friday in Baltimore if the swelling is down, yet he admitted there's a good chance that he won't pick up a bat that day.

"As soon as I can have some movement in my thumb to where I can feel like I can grip a bat and swing, then I'll be trying to press the issue and get back out there," he said.

Ryan Raburn started in Boesch's place on Thursday, batting second and playing left field against Cleveland's Fausto Carmona.

Confident Schlereth inspiring confidence

CLEVELAND -- The Tigers weren't planning on needing their bullpen for many outs on Thursday with Justin Verlander on the mound, so manager Jim Leyland went a day knowing that he could give lefty Daniel Schlereth some rest. But it's hard to tell what kind of shape the bullpen would have been in without Schlereth the last couple of nights.

Combine his two scoreless innings on Tuesday with his 1 2/3 scoreless on Wednesday, and Schlereth has tossed eight scoreless frames, allowing just three hits, since the Tigers called him up nearly two weeks ago. He has walked three and struck out seven in that span.

Leyland said that Schlereth's improvement is a matter of command, both with his curveball and his fastball. Though Schlereth said upon his return that his numbers were a product of the hitters he faced at Triple-A Toledo, Leyland said that he worked on his stuff while he was down there rather than simply looking for easy outs.

"He's a more confident pitcher right now," Leyland said.

The Tigers, in turn, are becoming increasingly confident in him.

Verlander to stay on regular schedule

CLEVELAND -- Justin Verlander, who took on the Indians on Thursday at Progressive Field, isn't in line to face them during their return trip at Comerica Park at the end of next week.

Verlander's next start is on Tuesday, against the Twins. With an off-day on Thursday, the Tigers have the option of keeping the rotation in order and giving Verlander an extra day of rest, or using him on his regular four days' rest.

Manager Jim Leyland said on Thursday that the plan is to keep the rotation in order, which would put Verlander in the opener at Tampa Bay on Aug. 22 rather than the series finale against Cleveland the previous day.