PITTSBURGH -- The Indians have lost six straight games going into Tuesday's series opener with the Pirates, but they have regained their All-Star center fielder.

Grady Sizemore was activated from the 15-day disabled list on Tuesday after resting and rehabbing his inflamed left elbow. It was a rare dose of good news for the Tribe, with another one hopefully on the way as Asdrubal Cabrera (sprained left shoulder joint) will likely be activated from the DL by the end of the week.

"It's good to have Grady back," manager Eric Wedge said. "And Asdrubal's going to be rehabbing at [Double-A] Akron for a couple days. The earliest we'd have him back is the third game here [on Thursday]."

When Cabrera comes back, he'll slot into Sizemore's former leadoff spot. So Sizemore's return on Tuesday saw him get the start in the No. 2 spot of the lineup, with Jamey Carroll hitting leadoff.

"The plan is to pop Asdrubal back up top, with Grady in the two-hole," Wedge said. "That's the way we had it before they got hurt, and I thought we were heading in the right direction."

To make room for Sizemore on the active roster, the Indians optioned outfielder Trevor Crowe back to Triple-A Columbus. And in a separate roster move impacting the bullpen, the Indians promoted left-hander Tony Sipp for the third time this year and designated right-hander Luis Vizcaino for assignment.

After three weeks on the pine, Sizemore will look to repair a season that got off to a subpar start. He was batting .223 with nine homers, 31 RBIs and a .726 OPS at the time he was placed on the DL on May 31.

While Sizemore was in Tuesday's lineup, he will have to be eased into everyday action, according to Wedge.

"He won't be playing every single day this first week," Wedge said. "Let's just take it day by day right now and go from there. Once we get back to the American League, we'll have some DH at-bats we can use, too."

Entering the week 13 games under .500 and 10 games back in the AL Central standings, the last-place Indians are hoping the returns of some key players will spark them. Sizemore will only do so if the elbow, which had been bothering him since Spring Training, continues to cooperate.

Arthroscopic surgery, which would have sidelined Sizemore for an additional four-to-six weeks, was avoided because the elbow responded well to treatment. Now, the Indians will see how it responds to in-game activity. The Indians did not take the extra precaution of having Sizemore take part in a Minor League rehab assignment prior to promoting him, as they did with the shortstop, Cabrera.

"Different players, with Grady's experience, and different types of injuries," Wedge said. "I had a good conversation with Grady, and he felt comfortable coming right back here. And with Asdrubal, we felt it was best for him to go down there. It just depends on the individual."

This was Sizemore's first trip to the disabled list in his career, and this was Crowe's second stint with the big league club this season. Crowe has hit .169 (11-for-65) over 30 games with the Tribe.

As for the move affecting the ever-evolving bullpen, Sipp is back for the third time, having been on the active roster from April 22-May 16 and June 1-9. He's made a total of 10 appearances, posting a 3.12 ERA with 10 walks and 10 strikeouts in 8 2/3 innings. At Columbus, he was 1-0 with one save and a 3.71 ERA in 12 games, striking out 22 and walking six in 17 innings. Left-handed batters were 2-for-19 off Sipp and he has allowed one run and no walks while striking out four in four innings of work since his last demotion to the Clippers.

Vizcaino and Greg Aquino helped stabilize the Tribe's wayward bullpen for a time, but both have been designated for assignment in the past week. Vizcaino went 1-3 with a 5.40 ERA in 11 appearances, striking out nine and walking 12 in 11 2/3 innings.