Torres' injury is different to the problem he picked up while on international duty.
A Liverpool spokesman told the club's website: "A scan this morning has shown a tear to a different adductor muscle to his original injury and we expect Fernando to be out for about three weeks.
"As for Xabi Alonso, an X-ray showed a fracture to the fourth metatarsal in his left foot.
"Xabi will be seen by a consultant tomorrow after which we will have a much better idea of the timescales involved.
"With regards to Javier Mascherano, he had an x-ray which has showed no bone injury, but he will receive intensive treatment on extensive bruising in his foot."