The Northern Ireland international has impressed during his 17 appearances since arriving at the end of September and Grayson is keen to keep him for an extended period.
Grayson said: "I've spoken to Steve Bruce and negotiations are ongoing. I'd like to bring him back if it's possible that we can sort something out and come to an agreement because he's done well.
"He can't play against Middlesbrough so that will give someone else a chance. There's a few options. (Andrew)) Hughesy, Ben Parker and Fede Bessone are all in contention."