The Boston Celtics are entering an offseason maze.

They have four players currently under contract for 2012-13. Kevin Garnett is pondering retirement and his decision figures to be the first domino to fall. But even Garnett’s choice will only begin to define an offseason which will require Danny Ainge to fill 11 roster spots while deciding whether to continue with the Big Three era past its expiration date or fully commit to rebuilding the Celtics around Rajon Rondo.

To make the scenario even more confusing, the decision isn’t entirely Ainge’s. Garnett could retire, Ray Allen could walk, Brandon Bass and Mickael Pietrus and Jeff Green and Chris Wilcox and Greg Stiemsma and a few other dudes who may or may not be worth mentioning could all leave for non-green pastures. The Celtics could potentially have a fair amount of cap space, but even that isn’t a certainty due to salary cap holds. Even if they do, the free agency crop is weak.

All of which leaves Boston’s destination (and 2012-13 roster) a mystery, even to owner Wyc Grousbeck. (WEEI)

“I think it’s fair to say when you look at the roster and you see who is under contract for next year starting with [Rajon] Rondo and [Paul] Pierce, and then you see who isn’t under contract — obviously a number of very good players are coming off deals with us including all the way to Brandon Bass and [Mickael] Pietrus and other people opting out or being free agents — the picture is not in place for next year yet. There are free agents available this summer as well from other teams, and there are a bunch of free agents available next summer from other teams, potentially.

“We can let this play out. We want to stay competitive. We want to stay contenders if we possibly can, but we really want to get banner 18, and sometimes you need a lot of luck to get a banner, I can tell you that. But we will see how this plays out over the next couple of years.”

So much could change, or so little. It’s easy to envision Ainge clearing house and starting the rebuilding process ASAP, and it’s easy to envision another year of the Big Three desperately attempting to hang on to their window of opportunity which should have closed years ago. (Though reports seem to agree Allen is pretty much a goner, the Celtics could very well have the most money to re-sign him. Also, there’s a familiarity in Boston which could pull him back in a sixth-man role even though he’ll probably have opportunities to start elsewhere.)

Change is coming. It might come swiftly, or it could begin gradually and take another year or two. But it’s coming, at some point, sooner or later, once the Celtics figure out a direction to navigate their way out of this maze of limbo.