The Celtics have nine unrestricted free agents -- counting Jeff Green -- and one restricted free agent in Greg Stiemsma. There’s a lot of uncertainty as they head into a summer that could produce anything from massive changes to subtle tweaks.

They can go over the cap to re-sign their own free agents using what’s known as the Larry Bird exception, but there are actually three classifications of Bird rights:

Full Bird: A player who has not changed teams via free agency for three consecutive seasons. Players with full Bird rights can be signed from anywhere from 1-5 years with raises of 7.5 percent up to the max amount. (Note: Just because they can sign max raises, doesn’t mean they have to. In other words, the Celtics could re-sign Kevin Garnett for any amount.)

Early Bird: A player who has not changed teams via free agency for two consecutive seasons. Early Bird players can be signed from 2-4 years up to 175 percent of their previous salary with maximum raises of 7.5 percent.

Non-Bird: All other unrestricted free agents. They can be signed for 1-4 years starting at a salary of 120 percent of their previous contract with a maximum of 4.5 percent annual raises.

Restricted: Subject to a qualifying offer that must be made by June 30, teams have three days to match an offer sheet from another team.

Here’s a look at each of them in relative order of importance.

KEVIN GARNETT
Status: Bird free agent

The last time we saw Garnett, he was locked in a mournful embrace with Doc Rivers after the coach removed him from Game 7 against Miami. You can read into that what you like, just as you can read into his decision to not speak to reporters after the game. Garnett’s status remains a mystery, and he holds the key to the rest of the offseason.

If he comes back for something in the $10 million to $15 million range, the Celtics would be close enough to the cap that it would make sense to bring back several of their free agents and possibly add another player using a cap exception. If he doesn’t, they could have cap room to play with, but probably not as much as people have anticipated. In order to use that cap room, they would have to cut ties with Garnett, who carries a $22 million cap hold.

Until that decision is made, the Celtics are in a bit of a bind. They would like to have him back, but at a price and length that makes sense for both sides.

There would be an interesting market for Garnett if he decided to test it. Dallas could make him the centerpiece of a renewed charge with Dirk Nowitzki. The Nets have been mentioned as they look to make Brooklyn more enticing for Dwight Howard and Deron Williams. He also would draw interest from every team with a mid-level exception, like San Antonio.

But it seems likely that Garnett will either play for the Celtics or retire, and that means everything to their present and future.

JEFF GREEN
Status: Full Bird

You were expecting Ray Allen?

Throughout the season, the Celtics have made Green feel as if he never left. He was often in the locker room before and after games, and even sat on the bench during the regular season against Miami. Green hasn’t talked to reporters except to exchange pleasantries, but his presence has been felt and it seems very likely that he will be back. 

It’s been a year-and-a-half since the Celtics acquired Green from the Thunder in the Kendrick Perkins trade, and there’s still an uncertain sense of what his role would be or how he’d mesh with Rajon Rondo on a full-time basis. Green never got comfortable in his half-season and he was looking forward to a bounceback year until heart surgery kept him out for the season.

Green remains an enigma, but an interesting one. Even in limited action last season, he and Rondo hooked up for a number of alley-oops and transition baskets, and his mix of speed, athleticism and savvy could help jumpstart the C's ailing transition game. He may not have a set position, but in a league where hybrid forwards can flourish in the right setting, Green would help make the Celtics more versatile and dynamic.

It’s likely that Green will be a part of their future, but at what price, and for how long?

BRANDON BASS
Status: Player option, Full Bird

Bass has a $4.25 million player option for next season, but he will exercise it and become a free agent. His market should be close to what Glen Davis received from the Magic: four years, $27 million.

Coming to Boston was a blessing for Bass, and he thrived under Doc Rivers’ tutelage, becoming one of the very few people who could coexist with the other four starters. The Celtics love jump-shooting big men, and Bass is one of the best in the league at knocking down 17-footers. He seamlessly moved from sixth man to starter and is capable of playing either role while maintaining consistent levels of production.

Bass feels like’s found a home in Boston, but the Celtics are still undersized up front and rebounding was their biggest issue this past season. Without a strong defensive anchor like Garnett, it would be tough to construct a new frontcourt around Bass and Green.

He could also be part of a sign-and-trade if they look to rebuild, and there will be a market for Bass because there’s always one for big men who score and play defense. Like almost everyone else, his return is dependent in part on Garnett.  

RAY ALLEN
Status: Full Bird

There’s a chance Allen could come back because there’s always a chance, but it seems unlikely. After four years as an All-Star component, Allen lost his starting job to Avery Bradley late in the season and was slowed by painful bone spurs throughout the playoffs.

While it wasn’t his preferred choice, Allen publicly accepted his new role and worked tirelessly to compensate for his injury. He probably should have had surgery sooner, but he elected to play through it and wound up logging over 38 minutes a game after Bradley was shutdown to undergo shoulder surgery.

Allen gave the Celtics five outstanding seasons and was more durable than anyone expected when he arrived from Seattle in 2008. If this is the end, he had an incredible ride in Boston where he outperformed expectations. (His 2010-11 season should be locked in a vault somewhere when he shot career-highs in field goal and 3-point percentage.)

Yet, it’s probably time to go. Allen will be in demand as both a shooter and a veteran presence who commands respect for his diligent practice habits and conditioning. The Heat, Knicks and Bulls may all be interested, but the Clippers would be a very intriguing fit. 

MICKAEL PIETRUS
Status: Non-Bird

He was billed as a defensive stopper and a streaky 3-point shooter, and that’s what he was during the regular season. Pietrus battled a knee injury that required surgery and his shooting went from streaky during the regular season -- 34 percent on 3-pointers -- to unreliable during the postseason when he made just 12-of-54 from behind the arc.

Still, Pietrus has value. If Bradley moves into the starting lineup full-time next season, the Celtics will need long, rangy reserves who can help out on bigger guards. He also adapted quickly to the Celtics locker room and was unafraid to speak his mind or be himself, two qualities that stood out in a positive manner.

As Pietrus is a non-Bird free agent, the Celtics are limited to offering him a contract starting at 120 percent of his previous salary, which for accounting purposes was $1.2 million.

GREG STIEMSMA
Status: Restricted

It’s not often you can discover a 26-year-old center who can make your team, and it’s even more rare to find one who can play. Stiemsma can play.

He saw action in 55 regular-season games and contributed a 19 percent defensive rebounding rate, and his 8.5 percent rate of blocking shots would have ranked second behind Serge Ibaka if he had played enough minutes to qualify. Stiemsma also showed an ability to knock down jump shots, and he helped save the season by grabbing the backup center job after Chris Wilcox had to leave the team to have heart surgery.

Stiemsma was slowed considerably by a foot injury, but when healthy he’s a legitimate backup center despite his tendency to commit fouls and turnovers. You’ve probably noticed that backup centers make a ton of money and have long careers whether they’re legitimate or not. Finding one like Stiemsma, who is very much legitimate, is a valuable asset.

The Celtics have to make him a qualifying offer of just over $1 million by June 30 to keep him a restricted free agent. Bringing him back seems like an obvious move.

KEYON DOOLING
Status: Early Bird

It took a while for the veteran guard to find his niche, but once he did he provided strong defense and some occasional 3-point shooting. Dooling struggled as a point guard during the regular season, but he proved to be a solid reserve in the playoffs and a locker room leader.

Like Bass, Dooling would love to return and there’s always room for a veteran player of his substance. The question again hinges on whether the Celtics face a full-on rebuilding project or look to tweak the roster.

Note: As Dooling is an Early Bird free agent, the Celtics would have to sign him to a two-year deal. They also could renounce his rights and bring him back on a one-year deal.

RYAN HOLLINS
Status: Non-Bird

There are other backup big men the Celtics could pursue, but there aren’t any others that can be re-signed using Bird rights. In limited time during the regular season, Hollins actually rebounded at a higher rate than in previous seasons and he had his moments in the playoffs, including seeing time in the fourth quarter of Game 7.

Still, there may not be room for Hollins, even as a third center. Sean Williams has a chance to stick around and JaJuan Johnson needs time to develop. Neither players are centers, but both have far more potential than Hollins, and there’s still the matter of the draft that could yield another big man or two.

MARQUIS DANIELS
Status: Non-Bird

Daniels did little in the regular season, but he had some key defensive stretches during the postseason. His return, like Sasha Pavlovic’s, depends on other personnel moves. The Celtics may need a veteran reserve on the wing, but they probably don’t need two.

SASHA PAVLOVIC
Status: Early Bird

See Daniels, Marquis.