Liverpool defender Fabio Aurelio will be out of action for up to a month with the hamstring injury he sustained during Sunday's victory over Manchester United.
The Brazilian limped off only 24 minutes into the 3-1 win at Anfield and the club on Tuesday confirmed he has suffered a tear to the muscle. Aurelio has been troubled by a series of niggling injuries this season and had only just returned from an adductor problem.
Liverpool's head of sports medicine and sports science, Dr Peter Brukner, told www.liverpoolfc.tv: "He's got a significant hamstring injury. Unfortunately his body lets him down. He always play well when he's fit. We've been managing him carefully because he's not been playing twice in a week, but this just came out of the blue."
He added: "He had a minor adductor strain a few weeks before that. We rehabilitated him and he trained all week with no problems at all.
"He's obviously very down. It was a sad sight to see him walking off the pitch. He's frustrated because he was playing well on Sunday. He was looking forward to getting a run of games but it wasn't to be."
Dr Brukner also revealed central defender Daniel Agger is unlikely to recover from a knee injury in time for Thursday's Europa League clash with Braga.
He said: "Daniel had a nasty kick on a joint to the side of his knee. It's an unusual spot to get an injury. They take time and he's a bit of a slow healer.
"He's still not 100% so we'll have to see if he's fit for the game this week. But it's more likely to be the following week."
Martin Kelly, who has a similar hamstring injury to Aurelio's, and Jonjo Shelvey (knee) will definitely miss the trip to Portugal.