Jurgen Klopp admits Liverpool must wait to discover the extent of Dejan Lovren's injury.
Lovren suffered a suspected hamstring problem that forced him off after 53 minutes of the 2-0 Champions League Group E win at Red Bull Salzburg here in Austria on Tuesday.
It was the second time in four days the centre-back departed early having been replaced before half-time in Saturday's 3-0 Premier League win at Bournemouth.
Read Paul Gorst's match verdict from the 2-0 win over Salzburg here
Lovren was limping as he left the Red Bull Arena and appeared unhappy at the issue.
The Croatia international will undergo tests when the Reds return to Melwood after securing their place in the Champions League knockout stages.
And Klopp says Liverpool are waiting anxiously on Lovren's fitness with Joe Gomez, his replacement, and Virgil van Dijk the only two fit senior centre-backs at the club.
“We hope it's exactly the same like last time he felt something and we made a decision,” said the Reds boss.
“It wasn't cool. He played really well and was very important in those 55 minutes.
“We don't know at the moment. Like last time, we have to see.”
