Noble will miss Tuesdays clash in Devon as he serves a one match suspension but O'Connor now misses the games with Torquay, Chesterfield and Bristol Rovers after collecting a straight red card at Burton.
Evans commented on themillers.co.uk, saying: "It would have been disappointing to lose one of those guys but to lose two is hard and for obvious reasons it will make our task even more difficult but we will get on with it.
"On top of that Daniel Nardiello is very doubtful but we will look at him on Tuesday afternoon before we make a final decision on him.
"With those two guys missing it will give two others a big opportunity to stake a claim for a regular place in the team. At Rotherham United it is performances in matches and training plus attitude that get you in the team, nothing else."