Gerrard has a history of groin problems and the latest injury has prompted increasing concern among the club’s medical staff.

“It’s a difficult situation and I don’t know exactly what it is,” said Benitez. “He has a pain his groin. We are working with him and he has no power. It’s not because of the muscle, it’s because of the pain in the muscle, so they are working there.

“Steven’s worried, he’s a little bit low because he thought he could be better. He cannot kick long balls properly. It’s not too much, but it’s enough that he cannot play comfortably.”

Benitez refused to be drawn on the possibility Gerrard could recover fitness in time for a call-up from England for their friendly against Brazil in Qatar next month.

“We cannot look one or two weeks ahead,” he said. “The main thing for us is we have an important game against Fulham in which he cannot play.

“Then we have an important game against Lyon and we have to check the situation every day, so I cannot talk about one or two weeks ahead.”

Benitez’s injury gloom was further deepened with the news Glen Johnson has suffered a small tear in his calf.

The England international will also miss this afternoon’s Craven Cottage encounter and could even be sidelined for the Lyon trip.

Philipp Degen is almost certain to make his first-ever Premier League start in place of Johnson at right-back today.

But with the Switzerland international not included in Liverpool’s Champions League squad and youngster Martin Kelly injured, Benitez could be without a recognised right-back in midweek for his team’s biggest game of the season thus far.

“Glen has a small tear in his calf and he cannot play,” said the Anfield manager. “Maybe he will be out for four or five days.”

Fernando Torres is among a clutch of players who will return after being rested for the Carling Cup tie at Arsenal on Wednesday, while Javier Mascherano has served his one-match suspension for the sending-off at Manchester United last Sunday.

Alberto Aquilani, who made his long-await debut at the Emirates, will travel with the squad despite picking up a virus that has affected other squad members during the week.

“Aquilani has a virus and could not train because of it,” said Benitez. “It is not swine flu, he just has a virus.

“Lucas and Torres were the same and were okay after one or two days so maybe it will be the same with Alberto.”