The England midfielder sustained a thigh strain in Wednesday's 3-1 home loss to Chelsea in the UEFA Champions league, and was doubtful for the second leg.
All the same, Benitez might take the risk of playing the 28-year-old in Liverpool's upcoming premiership game, which could aggravate his injury.
"Steven has some problems with his adductor. He will be in the squad but we still have to decide whether he will start," the Spanish tactician told Liverpool's official website.
"It is not very serious but we need to analyze the risk for the future as well. We know it's a very important game, so we'll decide tomorrow.
"We have to think about the best for Stevie and the team - both things together."
Benitez is yet to decide whether to deploy Gerrard against Blackburn or not, saying he will make up his mind several hours before the match.
"This is a very important game, so we know it will be really good if he can play. But if we were to lose him for the next few weeks it could be a big risk," he added.
"I will talk with him and the doctor on Saturday morning before deciding."