I think Grabner wants out.
He hasn't played a lot over the last two seasons, and there is a lot of competition on offense for this team. Grabner is going into the final year of his contract, and is going to be a UFA in a couple of months, so i imagine that Grabner wants to play.
I also think his groin is a bit of a mystery at this point, we know that he's had a lot of trouble with it over the last two seasons, and don't know if it will be 100% next season. Capuano has shown in the past that he doesn't want to put Grabner in the line-up when his groin is bothering him, when realistically he can play.