With a two-week window for preseason and free agency before the start of a 66-game regular season, Celtics president of basketball operations Danny Ainge (left) won't have much time to turn around a team that lost in the second round of last year's playoffs. Ainge has his work cut out for him as the Celtics have just six players under contract for this season. With that backdrop in mind, we look at some names who might fill out the rest of the roster.