England midfielder Gerrard limped off during Liverpool's 2-1 midweek defeat to French side Lyon in the Champions League while Spain striker Torres, who missed the game, is still struggling with a hamstring injury.
Right-back Glen Johnson is also doubtful for the crunch clash at Anfield.
"It's the same situation for all the players," Liverpool coach Rafael Benitez told the club's official website.
"We will speak with the physios over the weekend before making a decision about Steven.
"Hopefully Glen will be available but we'll have to wait and see. We will make late decisions with all of them."
Manchester United could also miss striker Wayne Rooney, who is suffering from a calf complaint.
"He is always desperate to play, that's the nature of the boy. It's going to be important how he does in training on Saturday," United manager Alex Ferguson said.