His current loan expires today and Barmby is hoping a deal can be agreed for Brady to stay at Hull.
"We'll know more when the January window opens," said Barmby in the Hull Daily Mail. "It's frustrating for everyone because we haven't got any news.
"Man Utd are well within their rights to put it on the back-burner because he's their player.
"We'll keep talking to them and we've got a good relationship with them but the ball is in their court.
"It's not down to us and that's unfortunate but we'll keep pursuing it and see where we go."