Best options for the retooling Celtics

Doc Rivers has set the bar. After watching the Miami Heat eliminate his Celtics in five games, Rivers said he came away with one, inescapable conclusion: The Celtics need to go a different route in 2011 if they expect to contend for a championship.

"We can't try to do the formula we used this year, just going to get a bunch of veterans and try to get through the regular season, because that doesn't work,'' Rivers said in a radio interview the day after the series ended. "In the playoffs now, with all the rule changes, you need athleticism, you need quickness to the ball. And quite honestly we just don't have that. That stood out to me more than anything in this series."

Make no mistake: The 2011-12 Boston Celtics will still revolve around the Big Four. All are under contract for the season (Ray Allen has a player option that he is expected to exercise). The team also could have contractual obligations to Jermaine O'Neal (one year at more than, ahem, $6.2 million), Shaquille O'Neal (a player option for around $1.4 million) and Avery Bradley (second year of his rookie contract).

That's six players who could be back, assuming Shaq does the right thing and hangs 'em up. Let's also assume the team will bring back Jeff Green, who fits what Rivers wants (young, versatile, quick and athletic) and Delonte West. Do we also include Glen Davis in that group? If so, you now have nine players. Nenad Krstic? That makes it 10.

One common thread I've heard in discussions about changes in the new collective bargaining agreement is that there could well be a reduction in rosters. Teams can now carry 15 players. For the sake of argument, suppose a new deal sets the limit at 13. That would leave roughly four available spots for the Celtics, three if they keep their first-round draft pick this year.

The Celtics are going to have to get their new bodies via free agency, whatever free agency looks like in the new NBA. They have no tradeable assets outside of the Big Four. (No one is going to touch Jermaine O'Neal at his number.) Trying to determine how much money they'd have available for free agents in a new marketplace is the NBA's version of tilting at windmills. The contracts of just seven players -- Kevin Garnett, Paul Pierce, Allen, Rajon Rondo, Jermaine O'Neal, Bradley and Green (using his restricted free agent figure) -- total more than $70 million.

We don't know what the new cap situation will be, but if the owners succeed in getting a hard cap, the Celtics still will likely have little, or anything, to offer. They can only hope that in the new deal, there are still methods for over-the-cap teams to bring in free agents -- and that there are free agents out there who are willing to come to Boston to compete for a title making less (a lot, in some cases) than what they made the year before or might expect to make going forward.

There currently are four major ways for the Celtics to sign free agents: by a sign-and-trade, by using available cap space, by using the mid-level exception and by using the biennial exception. The first two options appear dim unless they feel Big Baby might get something in a sign-and-trade. They conceivably could try to do the same with Green, but he should be in their plans. They won't have any significant cap space.

That brings us to the two exceptions. Most experts believe that if the mid-level exception is retained, it will be for a smaller number. The current mid-level can be divvied up to spend on more than one player. Will the new one? Will there even be a new one? The biennial exception now can be used once every two years. Will that survive?

So who is likely to be available when the smoke clears and the NBA re-opens for business? Here are a handful of suggestions for the Celtics culled from a list of the 2011 free agents. All are 31 or younger. All have a degree of athleticism.

Samuel Dalembert

The Celtics are going to need a center regardless of what happens with the O'Neals and Krstic. Dalembert is coming off a 6-year, $64 million deal, but he has never been close to playing on a winner. He is athletic and a good shot-blocker and doesn't need to be involved in the offense. But as one of the best free-agent centers available, he is likely to have many suitors. He's also durable; he has missed two games in the last five years.

Josh Howard

One of Danny Ainge's early regrets was not drafting Howard in 2003, when the Wake Forest forward was on the board. (He took a pick that he traded for Kendrick Perkins.) Howard has had health and personal issues, but that has never stopped the Celtics in the recent past. If he still has any hops left, he'll draw some interest.

Al Thornton

The Celtics liked this swingman a lot in the 2007 draft coming out of Florida State but ended up dealing their pick for Allen. (That worked out pretty well.) Thornton had a terrific rookie year for the Clippers but has bounced around (Wizards, Warriors) since then.

Carl Landry

The 6-foot-9 Hornets forward had a productive season, and New Orleans isn't going to break the bank to sign anyone, given its financial situation. He had an excellent playoff series against the Lakers, averaging 15.8 points and five rebounds a game. He's 6-foot-9, almost 250 pounds, so he would fill the void if Davis left.

There are others. Grant Hill doesn't fit the youth/athleticism/quickness description, but he will be a free agent and has a relationship with Rivers dating back to their days in Orlando. He has been a paragon of health in Phoenix after all those tough years with the Magic. Denver's J.R. Smith fits much of the Rivers' criteria and could be available. He's a bit of a head case. Tyson Chandler has been a difference-maker for the Mavericks but he is out of Boston's range.

Rivers isn't expecting a huge overhaul whatever happens at the bargaining table.

"We have to go out and sign a couple of players,'' he said. "We don't need any superstar. We need the right pieces to complement [the Big Three] so those guys can play less minutes and we can still win games and get to the playoffs healthy."

Of course, that's if there is a 2011-12 season and playoffs.

Longtime Celtics reporter Peter May is a frequent contributor to ESPNBoston.com.