Walsall travel to face the Reds on the back of five successive away defeats in the league and manager Merson was unhappy with their performance in the 2-1 reverse at Oldham on Tuesday.
He said: "I didn't see too many tired legs at the end.
"I expected to come away with at least a point and I hope it hurts the players as much as it does me."
Former Forest target Matty Fryatt will line up for Walsall. He has been linked this week with a move to Preston North End.