Daniel Sturridge's injury is not as bad as feared although Jurgen Klopp is not sure when he will be fit to return to his squad.
Sturridge suffered a hamstring problem after coming on as a 62nd-minute substitute during the 2-0 defeat at Newcastle on Sunday.
He had a scan on the injury on Tuesday and has been diagnosed with a 'strain' which is likely to keep him out of action for a couple of weeks.
That would see him miss the Premier League games against West Brom and Watford, as well as the Europa League clash with Sion on Thursday - although with Liverpool already through to the knockout stages, Klopp is expected to rest most of his key players.
Speaking 24 hours before the clash in Switzerland, Klopp said: "The injury [to Sturridge] is not that serious. It's a hamstring and it's not easy to say when he can be back for us.
"It's not that serious, but it's not possible to play. Now we have to build up his resistance. It is like it is. We have to help him be more resistant for all the games we have."
Sturridge, who is likely to be treated with 'kid gloves' by the club's medical staff due to his injury record, and Jordon Ibe missed training ahead of the Reds' flight to Switzerland on Wednesday afternoon - but Phillipe Coutinho, absent for the last three weeks with a hamstring strain - did train with the rest of the first-team squad.
England international Sturridge missed the start of the season after having surgery on his hip, and has had issues with a foot and his knee since Klopp's arrival at Anfield.
He returned to action as a substitute in the 1-0 victory over Swansea on November 29 and scored twice after being handed a start in the 6-1 Capital One Cup win at Southampton last week before dropping down to the bench for the clash with the Magpies.
His latest absence leaves Liverpool light of options up front, with only Christian Benteke and Divock Origi fully fit among their out-and-out strikers - as summer signing Danny Ings is likely to miss the rest of the season with a knee ligament injury.