Liverpool may be forced into a rethink over Mohamed Salah's future after the club confirmed striker Alexander Isak faces a lengthy spell on the sidelines.
The Premier League champions revealed Isak, 26, had surgery on an ankle injury that includes a fibula fracture on Monday.
Isak, signed from Newcastle for a British record £125 million in September, suffered the injury in the process of scoring Liverpool's opener in a 2-1 win at Tottenham Hotspur on Saturday.
The Sweden international was tackled by Tottenham defender Micky van de Ven and limped off immediately after his goal having only been introduced as a substitute at the start of the second half.
"Alexander Isak today successfully underwent surgery on the injury he sustained on Saturday," a Liverpool statement said.
"After diagnosis, an operation was completed today on an ankle injury that included a fibula fracture.
"Isak's rehabilitation will now continue at the AXA Training Centre, with no timeframe yet placed on his return."
Isak's injury is the latest setback in his disappointing start to his life with Liverpool.
He has scored just three goals in 16 appearances since completing his protracted move to Anfield.
A dispute with Newcastle United meant he did not have a proper pre-season programme and arrived at Liverpool well behind his teammates in terms of fitness.
His season was then interrupted by a groin injury.
Isak's absence will be a major blow for Reds boss Arne Slot, with Salah at the Africa Cup of Nations with Egypt and Cody Gakpo not ready to return from a muscle injury until early in the new year.
It leaves Slot with Hugo Ekitike, who has five goals in his past four games, and the little-used Federico Chiesa as his only senior forwards.
Salah, 33, departed for Morocco on Afcon duty following the 2-0 win over Brighton & Hove Albion on December 13.
The Egyptian played a role off the bench in that game, assisting Ekitike's second goal.
Salah had been dropped from the squad by manager Arne Slot for Liverpool's Uefa Champions League victory three days earlier, a 1-0 away to Inter Milan, following his public criticism of the Dutch coach and the club.
Though Slot told reporters after the Brighton match there was "no issue to resolve" with Salah, speculation has continued to mount that the player, third on the club's all-time scoring chart with 250 goals, will be sold in January.
Salah has endured a poor start to the campaign by his own high standards, scoring only five goals in his past 21 outings.
Liverpool, whose Premier League title defence collapsed after a shocking run of results, have climbed to fifth in the table after extending their unbeaten league run to five games.
Isak's injury may now force the club into a rethink on whether to move Salah on. He scored the winner in Egypt's opening Afcon match on Monday, a 2-1 victory over Zimbabwe. Depending on how far Egypt progress, Salah could potentially miss another seven games for Liverpool. There has been strong interest from the Saudi Pro League in Salah's services.
Conversely, Liverpool could still decide to move Salah on and identify a replacement.
Bournemouth winger Antoine Semenyo has been linked with a move to Anfield as has Barcelona star Raphinha.