Liverpool captain Steven Gerrard has been ruled out for up to six weeks with a hamstring injury.
Gerrard suffered the injury when attempting a shot during last weekend's 4-1 win over West Ham and had to be substituted after 56 minutes.
The 33-year-old underwent a scan on Monday, which confirmed that the midfielder will be sidelined for at least a month.
Gerrard will miss some key Premier League games for Liverpool during a busy Christmas period.
The Reds travel to Tottenham on Sunday before hosting Cardiff on 21 December, and they then face tricky trips to Manchester City and Chelsea on 26 and 29 December respectively.
Liverpool boss Brendan Rodgers is already without striker Daniel Sturridge, who was ruled out for up to eight weeks after suffering an ankle injury in training last month.
Gerrard has made 17 appearances for Liverpool this season, scoring three goals.
But Rodgers has backed Joe Allen and Lucas Leiva to fill the void in midfield left by Gerrard's injury.
"Steven is such an important player for us, but we have other players and dynamics in the team and they have to step up," Rodgers said earlier in the week.
"Lucas has been excellent for us and he has forced his way into the Brazil side, so he has that quality and experience to step up and take the responsibility.
"Joe looks like he did when he first came here with his movement, his body work and fluency on the ball and that's what we need right now.