Of course it is going to be his call. Some posters here have trashed other team members so relentlessly for playing for their national teams that they have to try to assert that a decision to do just that is being forced on Manu.
Manu has well and truly earned the right to make this decision for himself, whatever it is.
I just happen to hope, selfishly, that he decides not to risk playing until next season for the Spurs.
But given the nature of a stress fracture, it seems to me that Coach needs to be even more careful with his minutes next year because his body really doesn't seem to handle too much unrelieved work without serious consequences.