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9/3/2013 7:48 P.M. ET

Oblique strain could jeopardize Masterson's season

CLEVELAND -- Indians starter Justin Masterson will miss at least one start with a left oblique strain. His season might be over, but the Indians are hopeful that the right-hander can return before the end of the month.

Masterson underwent an MRI on Tuesday and was diagnosed with the oblique strain. He was removed from Monday's game against Baltimore after facing just five hitters because of what Cleveland described then as soreness on the left side of his ribcage.

"With these types of things, I think it's probably reasonable to think that he's going to miss a little time here," manager Terry Francona said. "The hope would be that it's not the rest of the season. But we'll just keep monitoring him and see how he's progressing. We're certainly not going to do something that's not in his best interest, either."

Masterson, a first-time All-Star this season, is 14-10 with a 3.52 ERA. The sinkerballer has been the most reliable starter in Cleveland's rotation, which means his continued absence could have an impact on the Tribe's playoff chances.

"It could be a short amount of time," Masterson said. "It could take a little bit."

The Indians entered Tuesday 3 1/2 games out of the second American League Wild Card spot.

On Monday, Masterson sensed some discomfort in the first inning but thought little of it. The pain worsened in the second inning, and the Indians figured it would be best to remove him.

Earlier this season, Masterson felt something similar, though it did not escalate in the same fashion.

"I guess it wanted to wait until later in the season, when it was more exciting and we had more stuff going on," Masterson said.

Right-hander Corey Kluber, who hasn't pitched since Aug. 5 because of a right middle finger sprain, will start in Masterson's place on Saturday against the Mets. Cleveland survived without Kluber in its rotation, and it will try to do so with Masterson out.

Moving forward, the team will rely heavily on Masterson's symptoms in deciding how to handle him. The pitcher said the soreness he felt Tuesday was no worse than it was the day before.

"Hopefully, that will go away in a few days," Masterson said, "and then we can kind of get aggressive with it and see what we can do."

Kluber set for return to mound on Saturday

CLEVELAND -- Instead of backing up Scott Kazmir on Friday -- as the Indians originally planned -- Corey Kluber will make his first appearance since early August on Saturday, when he starts in place of the injured Justin Masterson.

Kluber has been on the 15-day disabled list since Aug. 6 because of a right middle finger sprain. With Masterson set to miss at least one start, the Indians are relieved to be welcoming Kluber back into the rotation as the season nears its finish.

Manager Terry Francona said Kluber, who impressed during a simulated game on Monday, will probably be limited to between 75 and 80 pitches in his return.

"Some of that depends on how he gets there," Francona said Tuesday. "If he has to work real hard in a couple of innings, we need to be cognizant of that, and we will be. He threw the ball really well yesterday. I was kind of proud of him. For him to do that, it's pretty obvious he's worked his tail off."

When Cleveland fans last saw Kluber pitch, he held Detroit to six hits over 7 1/3 scoreless innings. Across 21 games (19 starts) this season, he is 7-5 with a 3.54 ERA.

Like Masterson and Kluber, Zach McAllister has also been limited because of injuries this year, meaning the Indians have probably garnered more experience than they'd like to when it comes to finding replacements for injured starters. The expanded roster that September allows for gives them options to adjust the rotation if something else goes wrong.

One player Cleveland could turn to in that event is Josh Tomlin, who was recalled from Triple-A Columbus on Tuesday.

"There may be opportunities for starts," Francona said. "Things change quickly, as we noticed yesterday. Right now, the plan is to have him throw out of the bullpen. He is definitely a candidate to start, if we need one."

Quote to note

"There's times when you see really good pitching. There's times when there's really good defense. And there's times when you're not swinging it very well. There's times when you don't get pitches to hit. That's why you try to be as consistent as you can over the course of a long year."
-- Francona, on the various reasons teams can go through offensive lulls and how such stretches can be overcome.

Smoke signals

• Righty Blake Wood pitched in Monday's game, making his first appearance for Cleveland and first Major League appearance since Sept. 28, 2011, when he played for Kansas City. Wood threw a scoreless frame against Baltimore, issuing two walks and no hits.

"I thought he was throwing really hard," Francona said of Wood, who had Tommy John surgery last year. "He was really firing it. I think it will be interesting to see, as he gets some outings under his belt, does he maintain that velocity, does he get a little bit more command? We'll see where that goes, because that's a big arm right there."

According to BrooksBaseball.net, Wood's average fastball speed on Monday was 97.5 mph.

• Entering Tuesday, the Tribe had averaged 2.7 runs per game over its past 10 contests, while being outscored, 40-27. In six of those games, Cleveland scored two runs or fewer.

• The Indians have gone seven straight games without committing an error. Their season high is nine straight, from May 15-24.

Mark Emery is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.