The Celtics need Kevin Garnett. That much is clear, at least to the Boston Globe's Bob Ryan.

And the good news, according to Sports Illustrated's Ian Thomsen, is that a) Garnett probably wants to return, and b) the team can put together a coherent plan to rebuild around him.

"Big trouble" is how Ryan -- appearing with Thomsen and Michael Felger on 'Sports Sunday' -- described where a Garnett-less Celtics team would be in 2012-13. "There is no available substitute at center this year . . . Free agency is going to get them anything. They're not trading for Dwight Howard. They're not upgrading in any way unless . . . director of basketball operations Danny Ainge can . . . somehow con somebody into thinking the 21st and 22nd picks of the first round, which the Celtics own, have some value . . . They need him."

But Thomsen thinks Garnett will be back.

"Going into the year, the word going out from people who know him and people around him, was that this was it, this was his last season," he said. "And then I think as things went along that he was playing great; moved to center, obviously he's was one of the top three centers in the NBA and got rejuvenated; and he loves playing for Doc Rivers . . . I don't think he wants to leave now."

He also thinks the Celts can craft a rebuilding strategy around Garnett.

"I think if he comes back then it's like a two-year window," said Thomsen. "Nobody over there's told me this, but I've just kind of looked at the numbers and you see that if they can sign Garnett for two years, the contract of Paul Pierce expires in two years, maybe they sign a bunch of other guys to two-year deals, and then they all expire at once. And they can rebuild with free agents around Rajon Rondo two years from now.

"And in the meantime they use these two years to invest in young players, playing with Kevin Garnett, playing with Paul Pierce, get these young guys to learn how to win, how to prepare like these old guys do. So when they're gone, the old guys are gone, the young players -- Avery Bradley, JaJuan Johnson, whoever it is coming in -- are able to pick up where they left off."