I can't really see PJ3 as a starting SF.  Doesn't have enough skills.  So, he's likely to get NBA minutes as a backup PF perhaps a backup SF.  So, with KG, JJJ and Sullinger at the 4, I just don't see where PJ3 fits in.
Imagine a lineup in a few years of:
Rondo
Bradley
PJ3
Sullinger
Melo
Where's the outside scoring, go to scorer?  Our SF needs to be a prototypical SF who can carry the load.  PJ3 is not that guy.
How's that ... feel better?