The Knicks wouldn't let him, but Marbury insisted he has no bitterness toward his former team.

"Not at all," he said. "Not at all. If I did, it would take away my joy."

Marbury's new team, the Boston Celtics, held their morning shootaround in Manhattan, not far from where the point guard and the Knicks completed a buyout of his contract last week. Marbury signed with the defending NBA champions once he cleared waivers and was preparing to play his third game for them later Wednesday in New Jersey.

The Celtics believe they got the backup ballhandler they needed to upgrade their bench, and coach Doc Rivers said Marbury gets a fresh start in Boston.

"He's done nothing wrong with me so he deserves that for us. I can't touch or don't want to go into what's happened in the past because there's nothing you can do about that," Rivers said. "I think he's learned from some of the mistakes he's made and we move on. For us, hopefully we can take advantage of the mistakes he's made in the past and make him a better player."

Marbury believed he would get a chance to play out the final season of his contract with the Knicks. New president Donnie Walsh told him to report to training camp in shape, which Marbury did, and he played well in a reserve role during the preseason.

While Walsh was open to giving Marbury a final chance in New York, Mike D'Antoni wasn't. Perhaps aware of the distractions Marbury created by feuding with former coaches Larry Brown and Isiah Thomas, D'Antoni kept him on the bench once the real games began.

"Basketball's always been something that I loved," Marbury said. "Not being able to play, like I said, it wasn't my doing, it was their doing. So they chose to go in that direction, so I had no control over the situation."

Walsh banished Marbury from the team in early December following a failed buyout negotiation and some public criticisms of D'Antoni in the New York Post. Marbury originally refused to give up more than $1 million of his $20.8 salary, so Walsh told him to stay home, remaining hopeful he could unload Marbury in a trade.

That meant the 32-year-old Marbury went more than a year without playing in a regular-season game, but he doesn't believe his time was wasted.

"It happened when it was supposed to happen," said Marbury, who had season-ending ankle surgery in January 2008. "A lot of different things happened off the court for me as far as for my business, so I can't really complain too much because I still had the opportunity to allow my company to grow off the court."

Despite the long layoff, Marbury had a strong debut Friday for the Celtics, scoring eight points in 13 minutes and sparking a key run in the fourth quarter of a 104-99 victory over Indiana. However, he was scoreless Sunday in a loss to Detroit.

Marbury believes he'll catch up quickly, saying Rivers and fellow guards Rajon Rondo and Eddie House have helped him learn the offense. Better yet for Marbury, he feels accepted by everyone on his new team.

"I have a clean slate. It means a lot because that's all I wanted to do this year was play basketball," Marbury said. "Now I have an opportunity to go forward and do what I wanted to do when I first came to training camp at the beginning of the year."