Thompson, a right winger, has a groin problem while centre-back Mirfin's injury is to a leg.
There is better news in the central midfielder area - Josh Wright and Michael O'Connor will both be fit to start, having had to be replaced in the second-half of last week's loss to Norwich CIty with knocks.
Sam Togwell also returns from the one-match suspension which kept him out of that defeat to the Canaries.