Martin Skrtel has suffered a setback in his battle to regain fitness and will return to action for Liverpool two or three weeks later than hoped.
The centreback tore a hamstring in the game at Watford on Dec. 20 and has been sorely missed, with the Reds left facing an injury crisis and a crowded fixture list.
Skrtel was one of a quartet of recovering players due to resume full training this week in the lead-up to Saturday's Premier League match at home to Sunderland. Daniel Sturridge, Divock Origi and Philippe Coutinho successfully rejoined their teammates at Melwood, but manager Jurgen Klopp revealed on Friday that training had not been possible for Skrtel.
"We had a problem with Martin Skrtel, he's a little bit re-injured," Klopp told a news conference. "He needs another two or three weeks, we have to see."
Klopp also said he was confident of seeing a reaction from his squad after Tuesday's 2-0 defeat away to leaders Leicester City, which he blamed on his side's decision-making.
Liverpool had matched their hosts, according to Klopp, who said they were "a few decisions" away from clicking. And he said the matter was being worked on with a view to seeing an improvement against Sunderland.
"We want -- and have -- to do better than we did against Leicester, because we were absolutely not satisfied with our performance," he said. "You have to strike back and that's what we have to do.
"We are at home and we need these points, that's what everybody has to know. Sunderland are maybe better or different than before, but we have to be too.
"My feeling after Leicester was that with a few better decisions we could have had a completely different result. Today we have a session where we will try to work on it, but first of all everybody, especially the players, knows that of course they can do better.
"It's not a problem of quality, it's in the moment where you have to open your eyes and decide which is the best option. We did not do that at Leicester. We shot in a few moments where it was not the best choice and sometimes our crosses were not clear enough to make something.
"[Leicester] were not better than we were on this evening, I think everybody could see. But at the end Jamie Vardy's first goal was not really a chance, only a goal that's good for him. I didn't like the second goal -- I saw it 20 times after, with slipping and things like this. An unlucky situation.
"It was not our best day and what you could see in this moment was that confidence makes a difference sometimes. It's not always about more, it's about decision-making, but it's not only to talk about. We have to do it and we know about it. I think it's one of the last steps we have to do but it's a big step. If we can do this then results will change."
Klopp added that there was no rift with Sunderland manager Sam Allardyce, who referred to him as a "soft German" following the reverse fixture at the Stadium of Light on Dec. 29, which Liverpool won 1-0.
"It was never a story with Sam," he said. "The 'soft' story? I have no problem. A lot of people have said worse things about me or thought worse things about me.
"There's no problem and I have big respect for Sam Allardyce. When we played first time against Sunderland I said then that they would stay in the Premier League because Sam is there. We will shake hands."