Sadio Mane has a hamstring injury but Liverpool do not yet know the extent of the problem, manager Jurgen Klopp said.
The Senegal star went off in the first half of the Premier League leaders 2-1 victory at Wolves on Thursday.
Mane pulled up when running for a Mohamed Salah pass and was replaced by Takumi Minamino 33 minutes in.
Klopp hopes the injury is not serious but will wait until further checks can be carried out on Friday.
Sadio, it s a real shame he had to go off, he told BBC Sport. Hopefully, it s not too bad, just a muscle tweak, but we will see tomorrow.
Klopp added in a news conference: He felt something in the hamstring. We don t know yet; we have to wait.
40 Liverpool are only the fifth team in English Football League history to remain unbeaten in 40+ consecutive matches (W35 D5), after Nottingham Forest (42, 1977-78), Arsenal (49, 2003-04), Chelsea (40, 2004-05) and Huddersfield Town (43, 2011). Unrelenting.
— OptaJoe (@OptaJoe)
Jordan Henderson s opener was cancelled out by Raul Jimenez and Wolves looked to be heading for what would have been a deserved point before Roberto Firmino struck in the 84th minute.
Klopp accepted his side were not at their best, with Wolves goal particularly frustrating, but he was delighted with Firmino s clinical composure.
We scored a wonderful goal, we had wonderful possession but the set-up from Wolves is so good yes, it s counter-attacking, but it s about being well in possession, using the width of the pitch, he said.
The goal from a counter-attack doesn t make sense when you re one-nil up, but okay.
We changed the system two or three times, we calmed it down. We had incredible chances in the first half and then at the end it was a magic moment from Bobby.
The boys are human. It was a little bit up and down. We had a discussion on the pitch, there was stuff to improve but set-pieces can bring us back in the game, a good bit of skill can bring us back in the game. Wolves were really strong but it s clear we could settle again.
You just have to find a way to win and have someone who makes the perfect decision and that was Bobby again.
