Liverpool manager Brendan Rodgers has confirmed captain Steven Gerrard sustained a hamstring injury in the 4-1 win over West Ham and could be a doubt.
The England skipper limped off midway through the second half after racing through the inside-right channel.
Rodgers gave no indication of how serious the problem was, but said the 33-year-old would be assessed in the next couple of days.
''It was his hamstring so we just need to see how it is,'' the Reds boss said in his post-match television interview. ''He was outstanding in his performance, the quality of his passing, but when he went to get that pass he felt a little tweak.''
Liverpool's form has got fans dreaming of a first return to the Champions League since 2009 but Rodgers prefers to focus on the short term.
"We'll just keep going and take each game one at a time," he told reporters. "We've got difficult games ahead but it was always going to be difficult from the first game.
"We'll just go to the next challenge. These were games that were tough for us last year. You give the respect to the players because they are actually making them look a lot more straightforward.
"[Saturday] was a good day for us - the other results were good and that's when you need to exploit it and we certainly did that. I'd give the supporters credit as well because they play a huge part in our drive and relentless desire to get goals and their encouragement was great for us."