Even though I've given up on the show, I will be pissed if he doesn't come back.

I'm 99.9% positive he will. I heard it was a money thing; they're paying Mike Chang's actor more, so they cut a bit of Puck to keep the budget balanced. Which considering how much Glee makes and how much they spend of costumes, etc, strikes me as a bit ridiculous, but there you have it.