Liverpool manager Jurgen Klopp says striker Philippe Coutinho will be assessed on Sunday morning ahead of away game against Newcastle United.
The 23-year-old was expected to be in the squad to face Southampton in mid-week but was not even on the bench.
And he will undergo further tests tomorrow to understand if he is ready to face Steve McClaren's side on Sunday afternoon.
"I like optimism, but with Phil [Coutinho] we were too optimistic. Sometimes it happens like this and there's nothing to criticise about it," Klopp told reporters on Friday.
"He tried everything he could, he trained near normally but he doesn't feel comfortable, so we have to take care of this.
"The muscle is a dangerous thing and always when you feel something or don't feel comfortable then stop. He has been training, we will wait and I can wait every day – it's no problem until somebody tells me he is available and then next time he'll play.
"Yesterday nobody gave me this sign, so we will have to wait [and see] today.
"Obviously he [Daniel Sturridge] did well in the last game and it was the plan beforehand together with the medical department that around 50, 55, 60 minutes would be good for him and good for us, so that's what we did.
"Of course, he felt each muscle after the game and that's normal because it was intensive. At this moment, he is available for the weekend and we'll have to see how he does this time.
"Hendo [Jordan Henderson] is a good example to explain why players have to be handled differently. He is a worker and he needs to be absolutely fit.
"For him, it's better how we've done it in the last two games. It's perfect to have him back as an option and on the bench so we can bring him into the game. It's very important for us.
"Hendo has made a big step in the last few weeks and that's the best news. There were some doubts about the heel [injury] and so on, but he feels good, really good.
"When you see who we will play in December and January – the Southampton win has given us some more problems in January [Capital One Cup semi-final]! – so it's important we can give him time to come in."