WALTHAM — As training camp winds down, the Celtics  have 13 players on guaranteed contracts and coach Doc Rivers  hinted that decision time is coming soon. Rivers said the team was likely to make a decision before or shortly after their final preseason game on Wednesday against Toronto.
As has been discussed throughout camp, Danny Ainge has acquired several players who will play multiple positions. Keyon Dooling  could line up alongside Rajon Rondo  in the backcourt. Marquis Daniels  can play the off guard spot and Brandon Bass  and Chris Wilcox  will mix and match at both frontcourt positions.
With that in mind, here’s what they have:
Point guards: Rajon, Rondo, Keyon Dooling
Centers: Jermaine O’Neal , Chris Wilcox
Also in camp: Greg Stiemsma , Gilbert Brown, Michael Sweetney
OPTION I: Stay in house
The 6-foot-11, 260-pound Stiemsma has impressed the coaching staff with his ability to block shots and Rivers likes his shooting touch from the elbows. It wouldn’t be a shock if he made the final roster and provided another big body up front. The list of free agent centers is thin and Stiemsma has more upside than the likes of Francisco Elson.
Brown could be another candidate to stick. He hasn’t had many opportunities in camp, but he’s long and athletic. Unfortunately for Brown, the Celtics already have two young guard prospects in Moore and Bradley and a third could be overkill.
Option II: Keep a roster spot, or two, open
ESPN reported  that Kenyon Martin ‘s Chinese team might release the veteran forward, allowing him to return to the NBA earlier than expected. It’s a tricky proposition  and may take weeks, if not months, to untangle, but Martin would be in demand if he becomes available.
J.R. Smith, Aaron Brooks and Wilson Chandler  are also playing in China and they knew when they signed their deals that they would have to finish out the season that ends in March. Chandler would be a perfect fit, but the Celtics can’t offer him more than the minimum unless they work out a sign-and-trade. The Nuggets are loaded with wing players after acquiring Rudy Fernandez and Corey Brewer  from Dallas and re-signing Arron Aflalo so Chandler’s situation is one to watch.
Option 3: Pick through the free agency remains
Again, the Celtics can’t offer more than the minimum.
James Posey  has been in decline since he left Boston and the 35-year-old is coming off the worst season of his career. His True Shooting Percentage has dropped from .587 with the Celtics to .568, .525 and an abysmal .485 last season with the Pacers. Posey remains a popular choice among fans who have memories of his versatility and toughness with the championship squad, but his best days are clearly behind him.
Al Thornton is younger at 28 years old, but he’s an inefficient scorer offensive player and defense has never been his forte.
DeShawn Stevenson  can shoot, and play defense. At least he did last season with the Mavericks, knocking down 38 percent of his 3-point attempts.
Speaking of defensive-minded 3-point specialists, Keith Bogans was cut by Chicago to make room for Rip Hamilton and while his defense isn’t as good as his reputation, he was solid for Tom Thibodeau’s Bulls. Of the remaining available players, Bogans could be the best fit for a team that lacks a veteran guard behind Allen.