WALTHAM, Mass. – Boston Celtics Coach Doc Rivers isn’t worried about his team’s lack of depth at center. He plans on using Kevin Garnett a lot more in that role this season.

Entering his 17th season in the NBA and his fifth with Boston, Garnett, a 6-foot-11 forward, has been the anchor of Boston’s defense since he was acquired from Minnesota. Now Rivers says he’ll probably be playing Garnett, a 14-time All Star, at center a lot more.

Rivers talked about the league’s shortage of good centers and feels as if Garnett may be one of his best options.

As trade rumors involving center Jermaine O’Neal continued to swirl around the team’s practice facility, Rivers had a quick answer when asked what he plans to do.

“We’ll move Kevin,” Rivers said. “He will play the 5 this year. I honestly don’t think that it’ll be a problem. When he was younger it would have been a problem.”

But why now? During his career, Garnett, a 23,000-plus point scorer, has been successful against forwards, using his size to get off his solid jumper.

“He’s older, bigger, stronger and can play both positions and can spread the floor from that position,” Rivers said. “He can play the whole game at center and it wouldn’t bother me at all.”

When Boston acquired Garnett from the Timberwolves during the summer of 2007, it had young and promising center Kendrick Perkins anchoring the middle.

But last year just before the trading deadline, Perkins was dealt to Oklahoma City in a deal that brought the Celtics a young talented forward in Jeff Green.

At the time, Boston President Danny Ainge felt that O’Neal and Shaquille O’Neal would be enough. Shaq missed most of the final months of the regular season and nearly all of the playoffs before retiring during the offseason.

Jermaine O’Neal was also in and out of the lineup as the season was winding down.

Now, they hope Garnett can fill the void.

But it’s a void Rivers has seen since his playing days.

“I was fortunate enough to play in the big era,” said Rivers, who played 14 years in the league from 1983-96.

“Right now there’s not many of them,” he said of the dearth of big men. “Dwight (Howard) and (Andrew) Bynum are two that come to mind. I might be missing one or two.”

Garnett echoed what his coach said last Friday: that Boston’s Big Three — Paul Pierce, Ray Allen and Garnett — may be in for its last run at a title.

The trio won the NBA crown in 2008, its first season together.

“Unfortunately it is from our standpoint,” Garnett said. “No one knows the certainty of the future. We’re just trying to embrace it.”

Now, his future may be in the middle of the offense and the defense a lot more this season — one that could be his last with his contract expiring after the season.