Liverpool's Glen Johnson set for month out of action

Johnson (on the ground) came off before Torres' late winner

Liverpool's Glen Johnson has been ruled out for "at least a month" with a medial ligament tear in his right knee, according to boss Rafael Benitez.

The full-back, who recently missed three games with a calf problem, was injured in the 1-0 win at Aston Villa.

"Johnson has a problem, so he'll see a specialist and then we'll talk but we know he'll be out for at least one month," said Benitez.

"But we are waiting for another opinion and then we'll know how long."

Captain Steven Gerrard has also struggled for fitness, while £20m midfielder Alberto Aquilani's debut was delayed by ankle trouble.

Liverpool's winner against Villa was scored by Spanish striker Fernando Torres, who has been hampered by a groin injury this season.

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Benitez revealed that Torres, whose injury-time winner resulted in him overtaking Roger Hunt as the quickest Liverpool player to reach 50 league goals (in 72 games) for the club, has more recently been troubled by an ankle injury.

"Fernando has had some problems with his ankle more than his groin and he has been working very hard with the fitness coach and the physio," added Benitez.

"It depends on how he feels - in terms of how many games he can play - but against Villa he was OK.

"We will have to assess things and see what happens. We will leave it with him but we need to keep him fit for the remainder of the season. That is the important thing."