Miller was ruled out for the remainder of the season on Friday after it was announced the striker suffered cruciate knee ligament damage in their Boxing Day win over Scunthorpe.
Defender Collins will also be out for up to two months after sustaining a triple fracture to his cheekbone. The former Leeds man underwent surgery immediately after the game.
Defender Tony McMahon will also be missing for the Blades as he serves a one-match suspension following his fifth yellow card of the season against the Iron.
Goalkeeper Mark Howard (thigh) and defender Lescinel Jean-Francois (knee) are working their way back to fitness but are unlikely to be risked against a side with just one win all year.