Vaughan is on loan at the City Ground from Sunderland.
Billy Davies: "He has picked up a fractured patella, which unfortunately will keep him out for the best part of three months.
"It's on a similar scale to the losses of Chris Cohen, Kelvin Wilson and Dexter Blackstock. David is a very important player. It's a huge blow for the club, the fans and the player himself.
"But we're developing a squad for the future, that is our objective when we sign this type of player, and we hope he'll be able to come back before the end of the season."