Last season, he was useful when Wall was out, even averaging 19.1 points, 5.1 rebounds, and 6.1 assists in the 13 games of December.
A very big question is how he will handle losing his starting job (as he should) when Rondo comes back. This is a guy who tweeted his December stat line last season to signal his displeasure at being benched.
The knock against Crawford has been his attitude and his unwillingness to play defense. Those are problems that could become prominent again if he becomes displeased with a decreased role.
I'm skeptical that players like this are able to hold it together for more than a season, but maybe Brad Stevens is the kind of coach who can get through to a player like Crawford.