Yes, that's what I'm hoping for also. Maybe Dean had to hurt Cas or vice versa down there, so that's why Dean doesn't want to talk about it and we don't see Cas. Of course I'm hoping they got "really close", all alone against the monsters, and Dean's embarrassed about that, but that'll never actually happen on the show. ;)

Cas might be off on his own hunt for someone and Dean didn't want to help him because he chose to be with Sam instead and now he has a bad conscience because he left Cas alone instead. Ah, we'll see. I'm excited he's even gonna be in the season at all. And Crowley will be in it a lot as well from what I gathered.