Central defender Michael Dawson and versatile Croatian Vedran Corluka both have ankle injuries while Kyle Walker and Younes Kaboul are cup-tied.
Midfielder Tom Huddlestone, who can play in defence, also missed last week's Premier League loss at Sunderland with an ankle injury along with Dawson and Corluka.
"Corluka hasn't kicked a ball. Until he starts kicking we don't know if it will hurt him," Redknapp told reporters on Friday. "Tom has got his ankle in a protective boot but he will train tomorrow hopefully."
"Michael Dawson has a bit of an ankle problem. He did it in the Portsmouth (league) game. He has been having treatment. We'll see how he is tomorrow. We won't play him unless we feel he is OK."
Central defender Ledley King, who struggles to train because of chronic knee problems and who has been missing since February, could come into the reckoning, Redknapp said.
"He will have a stretch and we will see how he feels," Redknapp said. "You never know with Ledley. He could be OK."
Winger Aaron Lennon, who has returned to training after a long absence because of a groin injury, is still not fit enough to return to action.
