Liverpool will be without midfielders Jordan Henderson and Stefan Bajcetic for the second leg of their Champions League last-16 tie at Real Madrid.
The Reds travel to Spain trailing 5-2 and Henderson has been ruled out through illness while 18-year-old Bajcetic has a thigh injury.
"Stefan, it's a stress response in his adductor, which is absolutely bad," said Liverpool boss Jurgen Klopp.
"He doesn't feel a lot but he is now out for I don't know exactly how long."
He added: "We have just to let it settle and then we will see when he can come back."