NEW YORK -- Was this the end for Jason Giambi? Or was it the beginning of something better, something beautiful?

It was after midnight on a glorious Monday night turned somber Tuesday morning. Giambi peeled off that Oakland A's uniform for the 167th time this year after a 5-3 loss to the Yankees that ended a season and ended a dream. Who knows what uniform he will be pulling on when he shows up for spring training next February?

It could be this one. It could be the uniform of that Yankees team that had just shoved his Oakland team through the postseason's trap door. It could be a Mets uniform or an Orioles uniform or a Yakult Swallows uniform, for that matter. Giambi left no clues, almost certainly because he doesn't know himself.

Asked about his future when he finally arrived at his locker at 12:40 a.m. ET, Giambi couldn't have been much more noncommittal.

"I don't know," he said. "I just finished a game tonight. I haven't even thought about it yet."

But his trip down to the free-agent "Who Wants To Be A $150-Millionaire" studios is just a few weeks away. The A's had their chance this spring to keep him from making that trip. Owner Steve Schott then balked at including the no-trade clause that would have sealed a six-year, $90-million deal. And that meant this day, inevitably, was coming and this winter was coming and free agency was coming.

For the last seven seasons, Giambi has worn that Athletics green and gold. But this winter, will his decision be about his affection for that green and gold and the men who wear it? Or will it just be about green?

At one point, Giambi slipped up, talking about next year -- this team's next year -- by saying, "Hopefully, we'll come back and be in this position again." But that was one sentence in a 10-minute conversation. If you were looking for other hints between the carefully chosen adverbs and dangling participles, there were just as many that indicated he'd taken off that Oakland shirt for the final time.

If this had indeed been his final game with this team, the box score will show he left a four-hit, two-RBI sayonara for them to remember him by. Asked if he thought this might have been his grand finale, Giambi said nothing to indicate it wasn't.

"If that's the case, so be it," he said. "You can't dwell on it. We've tried to work on it from both sides. We'll keep trying to work on it. If something happens, something happens."

But it's hard to remember another postseason series in the history of free agency in which a man was playing baseball for one team while being so openly coveted by the team in the other dugout.

Officially, the Yankees never said a word. Unofficially, it was so obvious they are saving him a few extra pinstripes, you half-expected to see George Steinbrenner up there on the Jumbotron, inviting him to dinner.

And earlier in this series, Giambi made no secret of his love for baseball life in the big city.

"Oh, definitely. I love to play here," he said. "You know, the biggest thing is, I've always loved the game and the people who have played it. I know a lot of the old players. My dad was a huge Mickey Mantle fan. I've always studied the game. I really believe that if you are going to love something and enjoy what you do, you should know the past and the players.

"Being able to talk to Reggie (Jackson) and things like that -- and the fans, the fans are what this game is all about. They love their players here. They are very knowledgeable of the game. You know, moving guys over, they are applauding -- where maybe other places are like, 'Oh, you made an out; you stink.' It's a lot of fun -- especially the history. You see the plaques in center field. To think Babe Ruth and Mantle and DiMaggio and all those guys have played on this field is pretty exciting."

But there is another side to this story, and that is Giambi's cult-like status on his own team. Johnny Damon, another free agent, said his own interest in staying in Oakland will be determined in great part by whether Giambi stays.

"It will depend on Jason," Damon said. "That's pretty clear. Jason is the cornerstone here."

He's not just the cornerstone. He's the entire ground floor. So his GM, Billy Beane, has been unable to make himself even think of a future without Giambi.

"The only thing more sacred than Jason around here," Beane said, "is my kid's college fund."

So the A's will try to figure something out. It is no secret their team is up for sale -- and was even close to being sold a couple of months ago, according to major-league sources. Those talks reportedly have cooled now. But if there is a change of ownership, that could easily mean a change in stance toward doing whatever it takes to keep Giambi.

Keeping him means building around one of the great leaders in the game and allowing him to help nurture one of baseball's most talented young nucleuses. Losing him would mean, in many ways, starting over.

If there was one moment in this last game that summed up Giambi's imposing stature on a team that has clearly been orbiting around his unique supernova, it came in the fifth inning.

The Yankees had just brought Mike Stanton in to relieve Roger Clemens -- in the fifth inning, remember -- just to face him. And on the first pitch Stanton threw him, Giambi fired a bullet into right field for an RBI single that drew the A's back to within one run, 4-3.

But when he looked up to see that the runner on first, Miguel Tejada, had stopped at second instead of hoofing it from first to third, Giambi convened another session of his never-ending leadership seminar.

He stared at Tejada angrily and waved toward third. Then, as if that message hadn't been clear enough, he marched over to Tejada after the inning ended with him stranded and repeated the message, loud and clear. No one else on this team could have delivered that missive with quite the same force or anywhere near the same meaning.

Two hours later, though, Giambi admitted he'd just gotten "all fired up" and that Tejada's explanation -- that he couldn't get thrown out at third there -- was rational enough. He said he'd actually gone back to Tejada later and apologized.

"That's just part of the game," Giambi said. "I play with a lot of intensity. I went up to him later and told him it was my fault. I was just trying to make something happen."

What he made happen, though, was a historic rebound that enabled the A's to become the first team ever to drop 10 games under .500 in any season and somehow boomerang all the way back to 100 wins. Then they went two games up on the mighty Yankees, only to get steamrolled by a runaway parade float.

"To me," Giambi said, "it's incredible we even got ourselves this far. The way we started, there were about five or six of us who thought we were going to wind up on other teams by the all-star break."

Instead, they wound up on the verge of ending those Yankees glory years. By next October, though, the man who led that charge could well be enjoying the latest edition of those glory years with a big NY on his cap. But the exhaustion on Giambi's face Tuesday morning said this was no time to be talking about that.

"All I can do now is go home and watch the rest of these playoff games," he said, "and go from there."

Yes. But go where? For the Oakland A's, that's as significant a question as this baseball winter can answer.

Jayson Stark is a senior writer for ESPN.com