I don't think we know anything about Zajac. I think if he became UFA when Atlanta first moved to Winnipeg that would of been his high point to move. Not everyone decides to go to their hometown club. Toronto apparently showed a lot of interest in Clarkson, but he stayed here. I see Zajac as a bit more loyal to the club than Parise. Parise just didn't want to go play in Minny, but he also wanted to play with Suter. I also think Zajac has been treated rather well by the Devils whereas there was some frustration in Parise with the coaching turnovers and what-not.
Clarkson never went UFA. I don't know where this 'Clarkson to Toronto' stuff got started, but apparently it won't end until his career does.
Let's not forget that both of Zajac's professional hockey playing brothers are doing so in the Devils' organization. While neither is on an NHL contract and could be snapped up by another team at season's end, I imagine it's nice the family that all of them are playing within a 250 mile radius.