MESA, Ariz. -- The chances of Grady Sizemore garnering enough spring at-bats to be deemed ready for Opening Day remain extremely slim. That does not mean the Indians are ready to rule him out for the start of the regular season.

Asked if Sizemore was ruled out for the season opener, Indians manager Manny Acta said he simply could not make that claim with three weeks remaining in Spring Training.

"It's not a foregone conclusion, no," Acta said during the club's workout on Thursday morning. "Until he's ready to get on the field and we can gauge how many at-bats we will be able to get him before Opening Day, we can't announce that decision."

The fact remains that there is no established timetable for when Sizemore might make his Cactus League debut this spring. Sizemore is currently rehabbing from microfracture surgery on his left knee and is still likely at least one week away from his first possible game action.

Indians head athletic trainer Lonnie Soloff noted earlier this week that Sizemore might begin a baserunning progression on Saturday or Sunday. On Friday, Sizemore will step up to the plate and face live pitching from Cleveland right-hander Anthony Reyes, who is coming back from a bout with mild elbow soreness.

Acta made it clear that the Indians are not looking too far ahead when it comes to Sizemore's rehab schedule.

"We're day to day," Acta said. "As cliche as it might sound, with Grady it's day to day. Every time he comes out here and stretches his workout regime a little bit, you have to wait until the next day to see how he responds. Everything has been good so far.

"He's doing the outfield drills and going through the whole workout, which is an improvement. Running the bases will be the next step. I think by next week he's probably going to be able to do it."

Sizemore, who played just 33 games last year before undergoing the knee surgery in June, has been limited to sprint and agility drills on soft ground up to this point. He has been taking batting practice and playing catch as well. Sizemore's baserunning program might last at least a week.

When Sizemore is cleared for a return to games, Acta said it would likely be in a Cactus League scenario. In a Minor League game setting, Cleveland would have more control over Sizemore's at-bats, but Acta said the quality of pitching in Major League games would help the team gauge his progress.

"When he's ready to play, it doesn't have to be Minor Leagues," Acta said. "The Major League field is probably going to be easier for him with guys having better command and stuff like that."

Many factors affect backup-catcher decision

MESA, Ariz. -- The Indians have reached the midway point in Spring Training, but the club appears no closer to narrowing down its list of candidates for the backup catching role. Lou Marson's primary competitors for the job are Luke Carlin and Paul Phillips.

"That one is probably going to go all the way to the last week to be honest with you," Indians manager Manny Acta said on Thursday. "There are different factors involved in there."

One element within the decision is whether Marson would benefit from regular playing time at Triple-A Columbus. Marson, 24, hit just .195 in 87 games with the Tribe a year ago. So far this spring, Acta has been impressed with what he has seen in Marson's swing mechanics.

"He's swung the bat better than last year in the few at-bats that he's had," Acta said. "He's driving the ball better than last year. Even in batting practice, he's got a better approach. This guy hit, man. This guy has hit before. It's not easy to hit up here.

"It takes guys sometimes a little longer to make the adjustment. He was not the Player of the Year in Double-A for the Phillies [in 2008] because he was able to catch and throw. We know there's more to it than we saw last year."

Another factor involved in Cleveland's decision is that the backup catcher could see more playing time behind the plate than a traditional backup. The Tribe wants to keep starting catcher Carlos Santana's bat in the lineup as often as possible, using him as a first baseman and designated hitter at times.

That scenario could potentially open up more playing time behind the plate for the backup. With a strong showing this spring, Marson -- acquired as part of the July 2009 trade that sent lefty Cliff Lee to the Phillies -- might convince the Indians he is still the man for the job.

"If we do find that out and he does prove here in camp that he should be the guy," Acta said, "that could make us change our mind [about possibly sending him to Triple-A]."

Tribe pleased with Donald's transition to third

MESA, Ariz. -- Indians third baseman Jason Donald stepped up to the plate at HoHoKam Park on Thursday afternoon, sending a pitch from Cubs right-hander Randy Wells into center field for a single. Donald said the rest is a blur.

"I blacked out," Donald quipped. "I didn't know what happened."

It only felt like it had been that long since Donald last got a hit.

After missing the past four days due to a left hand bruise -- the painful result of a fastball from White Sox starter Gavin Floyd on Saturday -- Donald made his return to Cleveland's lineup in Thursday's 2-1 loss. He got the nod at third base and finished 1-for-2 in the batter's box.

All in all, even with his hand wrapped in ice after his part in the game, Donald was happy with how things went.

"Everything felt good," Donald said, "other than just the soreness that's working itself out. But I trust it. It's in a much better place than it was a day or two ago."

As things currently stand, the 26-year-old Donald appears to be the front-runner for the vacancy at third base for the Tribe. Donald is a shortstop by trade, and has past experience at second base as well, but the Indians have been pleased so far with his transition to the hot corner.

"He's looked very comfortable at third base," Indians manager Manny Acta said. "We're happy with the way he has played defense and the way he's swung the bat. It's too bad getting hit robbed him of the opportunity of a couple extra games."

Prospect Kipnis earns high praise from Acta

MESA, Ariz. -- One player Indians manager Manny Acta wanted to get a good look at this spring was highly touted second baseman Jason Kipnis. So far, Acta has been thrilled with what he has seen from the youngster.

"He fits the description of the type of players we're trying to put together on this ballclub," Acta said on Thursday. "The blue-collar, dirtbag, run-through-a-wall, relentless type of guy. We're trying to get a bunch of guys and put them together like that and create a team that's going to make our fans proud."

Kipnis, 23, will likely begin this season at Triple-A Columbus after hitting .307 with 16 home runs, 32 doubles, eight triples, 74 RBIs and 96 runs scored in 133 games between Class A Kinston and Double-A Akron a year ago.

Last season was Kipnis' first as a second baseman after breaking into Cleveland's farm system as an outfielder. Early on this spring, Kipnis has looked solid at second base, impressing Acta.

"He's far ahead for anybody that has only played one year at second base," Acta said.

Smoke signals

Right fielder Shin-Soo Choo said his left elbow, which was sore earlier this spring, is getting closer to full strength. "I can throw 100 percent right now," Choo said on Thursday. "But I'm not doing that yet. ... Righty Justin Masterson logged three perfect innings against the Cubs on Thursday, piling up five strikeouts along the way. "We're making adjustments and building off of that," Masterson said. "And it was nice. A lot of runs have been scored lately against us. I got to at least set the tone." Cleveland had allowed 41 runs combined over its past three games. ... Indians manager Manny Acta noted that outfielder Chad Huffman (strained right hamstring) went through a full workout on Thursday and might be available to play in a game on Friday. Huffman, who is hitting .571 in six games this spring, has not played since Saturday. ... Righty Jeanmar Gomez logged three shutout innings against the Cubs on Thursday. He struck out three, walked one and allowed one hit. Acta noted that each contender for the fifth spot (Josh Tomlin, David Huff and Gomez) would each likely make one more start before the competition is narrowed down to two pitchers. ... Recently signed first baseman Nick Johnson, who is currently rehabbing from surgery on his right wrist, will likely join the Indians in camp some time this weekend. ... Acta said Thursday that he has started thinking about Cleveland's lineup, but the manager is not ready to discuss the possible scenarios. "Choo's going to hit third," Acta said with a smile. ... The Indians are getting closer to making their first roster cuts of the spring. Acta noted that the roster may see some trimming between Friday and Monday. ... Scheduled pitchers for Friday's game against the Mariners include Mitch Talbot (starting), Chad Durbin (spring debut), Doug Mathis, Justin Germano and Josh Judy.