PHOENIX -- Michael Brantley doesn't know what uniform he'll be wearing in three weeks, but at least he knows what number he'll be wearing.

It's the same number Brantley was wearing Monday, while starting for the Indians in center field and batting in the leadoff spot against the Brewers team that dealt him as part of the 2008 CC Sabathia trade.

"I have that No. 23 that I wore in September," Brantley said proudly. "That's a positive. Last year [in camp] I wore 61, which is not too bad. But at the same time, it's not 23."

Though you wouldn't know it by talking to him or by the flashes of brilliance he displays on the field against big league competition, Brantley isn't even 23, either. He's a 22-year-old kid -- akin to a senior in college -- who defies his youth in so many facets of his game yet who, nonetheless, is not a finished product.

Then again, the Indians aren't a finished product, either, which is why you'll find no shortage of people who would prefer to see Brantley manning left field on an everyday basis for the Tribe at the outset of 2010.

At the moment, that's not expected to happen. The Indians' signing of veteran Russell Branyan to be their starting first baseman is expected to push Matt LaPorta from first to left, which would then, in turn, bump Brantley back to Triple-A, allowing the cost-conscious Indians to avoid starting his arbitration clock prematurely.

Then again, Branyan, dealing with a herniated disc in his lower back, has yet to set foot on the field for batting practice, let alone a Cactus League game, so his potential preparedness for Opening Day seems very much in question.

Which brings us back to Brantley, as intriguing a prospect as the Indians possess and already the subject of much spring discussion.

Brantley has heard all the speculation about where he'll end up at the end of camp and how the Branyan signing will affect his whereabouts. But he hasn't changed his mindset.

"Branyan or no Branyan, it did not matter," he said. "I just wanted to compete and earn a job and just battle. I try to put up good at-bats, steal a few bases and show the overall aspects of my game."

He did so Monday, leading off the fourth inning with a single, advancing to second on a grounder, stealing third and heading home on Matt LaPorta's sacrifice fly. It was typical leadoff man's work -- the kind of work the Indians expect Brantley to be doing on a regular basis in the bigs someday.

Never did Brantley show off his game better than he did last September, when he was a late-season spark plug on a Tribe team guided by a lame-duck manager and losing games at a feverish pace. Brantley showed up just in time to take the leadoff and center field reins from an injured Grady Sizemore and reached base safely with a hit or walk in 25 of his 28 games played.

Whenever a rookie comes up and plays as if he's been here before, it catches attention, even if the rookie in question has a Major League pedigree (as Brantley, the son of former outfielder and hitting coach Mickey Brantley, does). But Brantley's sizzling September was made all the more remarkable by the fact that his numbers at Triple-A Columbus had been rather pedestrian, save for the 46 bags he swiped.

"For me, it was more mental," Brantley said. "I was pushing myself so hard mentally [at Triple-A] that I wasn't able to perform to the best of my abilities. I was trying to do way too much and show the Indians they made a great choice in the trade. But I just learned to play my game, and I took that [approach] to the Major League level."

The thought of taking that approach back to the Minors doesn't appear to faze Brantley. He's smart enough to understand the business side of the game and the fact that if the Indians keep him on their Opening Day roster, his arbitration clock will start ticking.

Whether the Indians admit it publicly or not, that was a factor in the decision to sign Branyan, though the lingering questions about Branyan's back add a layer of drama to Brantley's outlook. Of course, the presence of veteran Austin Kearns, brought in on a Minor League contract, also has the potential to impact him.

"At the end of camp, we'll find out where I'm going," Brantley said. "It's up in the air. There's nothing I can do except play on the field. I try not to worry about where I'm going or what people are saying."

One thing people are saying about Brantley this spring is that the noticeable bulk he put on with a rigorous offseason weight-training program has added a little more thump to his swing. The knock on Brantley last year was that he was essentially a singles hitter, notching just 29 extra-base hits in Triple-A and four in the Majors.

Brantley added about 10 pounds of muscle in the offseason, and he hopes it will help him drive the ball to the gaps with more consistency. He also feels stronger in the legs, which could help him on the basepaths.

"It was all good weight," Brantley said. "I'm happy with the weight I put on. I'm holding it well. I can still run, and I still feel athletic. As long as I can hold the weight, I'll keep it."

Whether or not the Indians keep Brantley aboard, he has work to do. And general manager Mark Shapiro, for one, has been quick to point out that sending Brantley back to Triple-A might be the best for all involved.

"He's 22 years old, he had a solid but not special Triple-A season, and he had 100 good plate appearances up here, whatever that means," Shapiro said. "He does have an approach on the field that's above his chronological age. That being said, there's benefits to him being here, and there's benefits to him being in the Minor Leagues."

For now, Brantley's job is to make the decision as difficult as possible for the Indians. And even if he's sent to Columbus, he'll take pride in his number and wait to hear his name.

"I feel great when I see that 23," he said. "Any time I come in and see my name on the back of a jersey, that means I'm still playing baseball, and I'm happy."