The next Cal Ripken, Brooks Robinson and Scott Rolen all rolled into one sleeps on an air mattress in the living room of an apartment here in town. Oh, it's a nice air mattress, Ryan Zimmerman is quick to say, and the living room itself is pretty large, leaving plenty of space for Dan DeMent, his teammate on the Harrisburg Senators, to sleep on the other side of the floor.

Three other teammates have their own bedrooms with their own beds. But the next Cal Ripken, Brooks Robinson and Scott Rolen doesn't feel the slight.

Instead, he gratefully said, "I was lucky to get into this apartment."

Around him his roommates chuckle, knowing the 21-year-old man on the air mattress could afford to buy his own mansion with his $2.9 million bonus from the Nationals. They know he's going to the major leagues, perhaps in a matter of days. In fact, when the Senators manager, Keith Bodie, called him into the office Wednesday they immediately surmised the promotion had come.

It turned out Zimmerman was being told that Nationals General Manager Jim Bowden wanted him to move from third base to shortstop for whatever days he has left in Class AA.

"That was my second guess," DeMent said.

If there was a way Zimmerman thought he could slip into minor league life, sleeping on the floor of an overcrowded apartment without drawing notice, he has failed. The talent is impossible to miss. He doesn't move on the field as much as glide, sliding with the lanky assuredness of an athlete who knows he is good but is trying hard to seem inconspicuous.

"Did you see his first game at shortstop?" Nationals roving infield coordinator Jose Alguacil asked, his eyes wide, Thursday night. "He can pick it. I tip my hat to the kid and when I say that it's something special."

There seems little doubt anymore about the Nationals' plans for their top pick in this summer's draft, the No. 4 choice overall. His immediate future in Washington was probably sealed on Wednesday when Bowden announced that Zimmerman -- with about 200 professional at-bats -- would be playing shortstop even though he was a third baseman all the way through the University of Virginia.

Bowden's comparison of Zimmerman to Ripken, Robinson and Rolen further raised the stakes, drawing a shy laugh from Zimmerman.

"I would be lying to you if I told you I was not thinking about it," Zimmerman said of his impending promotion. "A lot of people think you are being cocky if you think about it, but if you're close why not work a little bit harder? It might get you a couple extra hits you need and who knows? That might get you the call-up. And then who knows? Maybe you stick. Or maybe you won't but you'll get a taste of what you need to know to get back."

He has already pestered the former major leaguers who have come through Harrisburg -- Kenny Kelly and Dee Brown -- with questions about big-league life. He can't help but notice that special things are being done for him, things like a half-week apprenticeship at Class A Savannah before the express ticket here and the sudden move of shortstop Josh Labandeira to third to make room for him.

"It's awkward," Zimmerman said. "Sometimes, you feel bad because there are guys who have been playing here all year."

What can he do? Everyone seems to understand. On Thursday -- before the Senators played their last home game before a weeklong road trip -- fans, batboys and people around the team kept offering their goodbyes. Nobody expects him to be here when the team returns next Friday.

It seems they all have Ryan Zimmerman stories -- the two 150-foot runs on back-to-back nights to catch long foul fly balls, the home run on the pavilion way beyond the 20-foot-high left-center field wall, the line-drive doubles to the opposite field.

Suddenly Bowden's ravings don't sound so preposterous.

"I'm serious, the guy is a prospect to win a Gold Glove in the big leagues," Alguacil said.

As a shortstop or third baseman?

"Either," Alguacil said.

He's coming soon.