Liverpool have confirmed Alexander Isak suffered a leg fracture during Liverpool's 2-1 win over Tottenham on Saturday.
The Sweden striker underwent surgery on Monday and while there is no timescale offered on the injury, the 26-year-old is expected to be out for a few months.
Spurs defender Micky van de Ven slid into Isak as he attempted to prevent the striker from scoring, leaving Isak unable to celebrate as he immediately signalled for medical attention.
A stretcher was brought onto the pitch but Isak eventually left the field with the help of Liverpool's medical staff.
Liverpool said in a statement: "After diagnosis, an operation was completed today [Monday] 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 was sidelined for five games from October to November with a groin injury and the latest setback will only compound his disjointed start to life in Liverpool since completing his record-breaking ÂŁ125m move from Newcastle this summer.
Isak has scored just three goals across 16 appearances in all competitions for Liverpool.
Your Site' Jamie Carragher:
"One thing is for certain now, Mo Salah will be staying at the club. There's a good chance Harvey Elliott would come back from Aston Villa as well.
"Whether Liverpool go for a striker or another attacking player like Semenyo, who Liverpool have been heavily linked with as well, we all know he's got a buyout clause in January.
"Then you've got wide players, as in Salah and Gakpo, who've played a lot of games through the middle as well. You've got young Jayden Danns.
"That's the way they could go around it because I don't think Liverpool, when you go back a few years, when they had a real problem at centre-back, they didn't go and spend big money on someone they didn't want.
"They won't go out and buy a striker who they don't really want. If they do want Semenyo, that's probably a good way around it."
Your Site' Rich Morgan:
Isak missed four matches at the end of October and start of November with a groin injury which forced him off at half-time of the Champions League win over Eintracht Frankfurt.
He has started five out of nine since returning but any absence now, however lengthy, will be a blow with Mohamed Salah at the Africa Cup of Nations and Cody Gakpo not ready to return from a muscle injury until early in the new year.
It leaves Slot with just Hugo Ekitike, who has five goals in his last four games, and the little-used Federico Chiesa as his only senior forwards.
Unlike Isak, Ekitike has hit the ground running since moving to Anfield from Frankfurt for ÂŁ79m last summer, scoring 11 times in 24 games in all competitions so far this season, including eight in the Premier League.
And now in Isak's injury-enforced absence, the 23-year-old has the opportunity to stake his claim as the champions' first-choice No 9 during a crucial run of fixtures.
