WALTHAM, Mass. (AP) – Antoine Walker was back at the Boston Celtics’ suburban workout facility, back in the familiar green, back on the practice parquet. The only visible difference was the No. 51 on the spare warmup jersey he grabbed, and the smile on his face.

Chucking up 3-pointers – relax, Celtics fans, it’s only practice – Walker was happy to be back in Boston after his exile on the Dallas bench and NBA purgatory with the bottom-dwelling Atlanta Hawks. So happy that he’s willing to put his problems with Celtics basketball boss Danny Ainge, whom he once called a snake, in the past.

“I give Danny a lot of credit for bringing me back. That takes a lot for anyone to do,” Walker said Tuesday as he prepared for his first game back in Boston with the Celtics. “I said things I didn’t really mean, and I’m sure he said things he probably didn’t mean.”

Walker called himself a more mature player than the one that left Boston 11/2 years ago when Ainge sent him to Dallas – as much to break his stranglehold in the locker room as on the court. The Mavericks sent him to Atlanta last summer, and the Hawks bailed out on him last week to get a future first-round draft pick.

“It lifted my spirits up to come back to a team that can win,” Walker said as he looked toward Wednesday night’s game against the Los Angeles Lakers. “It’s going to be very exciting for me.”

A No. 1 draft pick in 1996, Walker played seven years in Boston and became the face of the franchise. He made three all-star teams, carried the Celtics to the 2002 Eastern Conference finals and, with Paul Pierce, accounted for a bigger portion of the team’s points than any duo in the league but Shaquille O’Neal and Kobe Bryant.

But soon after Ainge took over the Celtics’ basketball operations, he determined that he wouldn’t pay the maximum price Walker wanted in an extension. The concern that Walker wouldn’t be happy after the snub apparently prompted Ainge to ship him to Dallas.

Walker lashed out.

That was then.

“I’m just happy to be back in the place where I started my career, and I’ve had success,” he said.

But more has changed than stayed the same for the Celtics since Walker’s departure. Jim O’Brien is no longer the coach, and with him went the perpetual 3-point shooting that had Walker stationed at the perimeter instead of banging under the basket.

“Philosophies changed. We just haven’t shot the 3 a whole lot,” coach Doc Rivers said. “He’s been fine with it.”

Rivers, who was the coach of the Orlando Magic for part of that time, said Walker let opponents off the hook when he strayed from the basket.

“I thought he was easier to guard then than he is now,” Rivers said. “All we knew was, we didn’t want him in the box. If he made 3s and beat us, we felt, We’ll live with that.’ When he beat us down low, it killed us.”

For the record: Walker said he shot 3-pointers because that’s what O’Brien and Rick Pitino before him wanted, not because Walker was unwilling to play the post.

“I’m a versatile forward,” he said. “On this team, we have a lot of perimeter guys so I’m not needed there. … I’m going to do whatever it takes to help this team win.”

Rivers said he’s thrilled with the trade – and what’s not to like? The Celtics are 2-0 since acquiring Walker for Gary Payton, Michael Stewart and Tom Gugliotta to improve their lead in the lackluster Atlantic Division to two games over the Philadelphia 76ers.

And the trade could get even better.

The Hawks are considering whether to put Payton on waivers, which would give the Celtics a chance to re-sign him. Rivers said Boston is one of six or seven teams interested in the nine-time all-star, but the Celtics are sparing no efforts.

Pierce and Ricky Davis have called Payton to ask him to come back. Rivers spoke with him on Monday and said that Payton would be happy to come back to Boston, though he was keeping his options open.

It would be quite a turnaround for Payton, who was reluctant to report to Boston when he was first traded here from the Los Angeles Lakers last summer.

“I would love to have him back,” Rivers said. “When we made the trade (to acquire Payton), no one wanted him. Now six or seven teams want him. So that means he did his job very well here. I think he’s made himself very attractive with what he’s done here.”

Also Tuesday, Rivers said that guard Tony Allen will miss the Lakers game because of a sprained ankle. Pierce was expected to play despite skipping practice on Tuesday with a sore left knee; Pierce banged knees with Shawn Marion in Monday night’s game against Phoenix.

AP-ES-03-01-05 1903EST