Carey has a leg problem so Jamie McAllister could continue to deputise in defence, while Brown is recovering from a badly bruised leg.
Millwall welcome back winger Chris Hackett from suspension and on-loan Charlie Lee is available again.
Zak Whitbread is doubtful, while Jody Morris and Neal Ardley are both out, along with Tony Craig, Mark Phillips, Derek McInnes and Tom Brighton (ankle).