You need to consider the style of ball the Celtics want to play.
Mozgov and Hibbert will not work with the style the Celtics have chosen to play about 70% of the time.
Each well run NBA team, makes a decision on the style of ball they want to play. They then begin gathering players that fit into this style. The C's have chosen, (for better or worse) the more modern small ball, ball movement, stretch 4 & 5 concept.
Just throwing in a Mozgov or a Hibbert is not going to work, unless you have your small ball rotation set in stone. The C's don't... their still looking for major parts to the small ball rotation.