"Steven Gerrard is a little bit tired," said Benitez. "He did not train the day after the England game but he was back in training on Friday.
"He has had a problem before with his groin and he has picked up another one on the other leg.
"He has already missed 10-15 days of training.
"That is the reason he was not playing from the start against Standard Liege.
"It was clear that he could not be fully fit after that. He would be Superman, no?
"But we know that he will be better and better. At the moment our idea is to protect the player."