Liverpool will be without Andriy Voronin for up to six weeks after the Ukraine striker picked up an ankle injury.
The 28-year-old summer signing from Bayer Leverkusen has missed the last two games and scans on the ankle injury have revealed the problem is worse than was first thought and requires surgery.
Voronin is now likely to miss the Reds' next eight games - including next month's first leg of their Champions League last 16 tie with Internazionale.
The versatile striker has fallen out of favour in recent months, but started the season in impressive fashion.
He scored three times in his first four appearances following a free transfer switch from the Bundesliga in July.
Voronin has scored four times in 23 appearances in all competitions this season.
Meanwhile, manager Rafael Benitez has also confirmed that defender Daniel Agger is still a couple of weeks away from a possible first-team return after suffering a recurrence of a metatarsal injury.
Full-back Alvaro Arbeloa will also be sidelined for the next three weeks with an abdominal problem.