Liverpool manager Jurgen Klopp is still waiting to discover the full extent of Divock Origi's hamstring injury.
Origi sustained the problem during the first half of Liverpool's 1-0 victory over Premier League leaders Leicester on Boxing Day and was replaced by Christian Benteke, who went on to score the game's winning goal in the second-half.
The Belgium forward underwent a scan following the match at Anfield, but Klopp announced he is yet to receive the test results, leaving Benteke as his only fit senior forward.
However, Klopp did reveal winger Jordon Ibe has returned to training following illness and James Milner will begin training at Melwood on Tuesday after a spell on the sidelines with a calf injury.
Liverpool face Sunderland at the Stadium of Light on Wednesday - live on Sky Sports 1 HD from 7pm - and Klopp has also backed Benteke to adapt to his style of play and begin scoring for the club on a consistent basis.
"He knows what he has to do. That's for sure. It was not too easy to come in (against Leicester), but the second half was better," Klopp said.
"He has such potential. It's always, if he doesn't play perfect, there's a little bit. He's not the same striker as Daniel [Sturridge] or Divock.
"We have to use his natural skills, and he has to try and be more involved in the game. Then we can make steps together. It's not possible for a player to play his own style against the team.
"Of course a striker has to make goals. That's what we need him for. We are clear. Now we can work."