From TG's article the other day, he seemed adamant about getting a contract and not just a camp invite.
I'm assuming, if he doesn't re-sign, that's why.
Lou probably wanted to get another look at him in camp, but Sykora (and not entirely unjustified) probably figured a 21-goal performance deserves more than that.
So... which GM is planning to throw $1-2 million at him?
If Sykora gets a two-year deal, which I doubt, can't fault Lou one bit. If he gets a one-year deal then he'd better have something else up his sleeve besides Butler. Even if you want to argue he's finished and the second half proved it after he played on emotion in the first half.