While I absolutely am concerned about Gronk's hip (I'd be concerned about ANY injury to him, he's arguably our second-most important offensive player) I don't really feel as though his injury history comes into play here- his previous injuries were to his back and his ankle, so this would seem to be unrelated. Unless it's a back problem manifesting as hip pain, then all bets are off, but I doubt that.
As for what his diagnosis is, who the hell knows - "hip pain" could be so many different things - hip flexor, hip pointer, labrum - we'll obviously never know unless and until he has surgery - let's hope it doesn't come to that.
Sal Pal was on SportsCenter this morning and reported that Gronkowski was a big concern with his back as well. He talked to Mike Reiss and he said the team is concerned. Great.