Liverpool will discover the full extent of Philippe Coutinho's injury when he undergoes a scan on Monday afternoon, a source has told ESPN FC.
Coutinho, 24, was carried off on a stretcher in the 34th minute of the Reds' 2-0 win over Sunderland at Anfield on Saturday afternoon.
The Brazil international was challenged by Didier Ndong and immediately called for the attention of the medical staff before he was taken off.
A source told ESPN FC that the "likelihood" of Coutinho's injury is ankle ligament damage and that he was present at the club's training ground Melwood on Sunday on crutches with his right foot in a protective boot.
Liverpool manager Jurgen Klopp told a news conference on Saturday that Coutinho's pain had decreased when he spoke to him at half-time of the Sunderland game.
"He had pain," Klopp said. "It was very painful in the first moment, but when I saw him at half-time he said the pain was much better.
"But we have to wait. If I have no idea what it is then I can't imagine how long it will be. I'm quite an optimistic guy, so I hope he can train tomorrow!"
There is positive news for Liverpool regarding Roberto Firmino as a source has told ESPN FC that it does not appear the forward will require a scan on his calf.
Firmino came off in the 87th minute on Saturday with a slight limp due to "pain in his calf" following a kick, according to Klopp.
Daniel Sturridge missed the meeting with David Moyes' side and was unable to train at Melwood on Sunday.
Meanwhile, Adam Lallana continues his comeback from an injury sustained on international duty with England that has kept him on the sidelines for Liverpool's previous two games.
A source said that the midfielder is continuing to train outside with the club's fitness coaches and is "making good progress."