I don't think he was complaining, just stating the obvious. He doesn't know what role he will be asked to fill next season. The Celtics don't know what role they will ask him to fill next season. If he is with the team, at some point, the Celtics will say OK, here is your role. Problem solved.
I think he is a useful player. We don't have so many options to defend at the PF (I am not one that thinks Tatum can do it). I am hopeful that we bring in a legit starting PF or C for next season and that the role for Morris is versatile bench player.