Liverpool have said the Sweden striker "successfully underwent surgery" on an ankle injury that included a fibula fracture. The club have not yet confirmed a return date, but Isak is expected to be sidelined for at least a few months.
The 26-year-old was injured during Saturday's match at Tottenham after coming off the bench to score for Arne Slot's side in the 2-1 win. Isak was caught by a challenge from Micky van de Ven just after striking the ball for his goal. He was clearly in pain, received treatment on the pitch and was helped off by Liverpool's medical staff, unable to continue.
Liverpool confirmed the extent of the injury following further assessment, with the club adding that the operation had been successful.
Isak joined Liverpool in the summer in a Premier League record deal worth one hundred and twenty-five million pounds. Since arriving from Newcastle in September, he has scored three goals in 16 appearances in all competitions.
The injury has come during a difficult spell for the forward. During the summer, Newcastle left him out of their pre-season tour of Asia with what the club described as a minor thigh injury, while it was widely understood the player wanted to explore a move away. Isak later trained alone at his former club Real Sociedad before completing his switch to Liverpool on deadline day.
He made his Liverpool debut in a Champions League win against Atletico Madrid on 17 September and scored his first goal for the club in a 2-1 victory over Southampton.
His first league goal for Slot's side came at West Ham on 30 November, followed by his strike against Tottenham that ultimately led to this latest setback.
Liverpool now face a period without the striker as they await further updates on his recovery.
Arne Slot has said Conor Bradley is a "50-50" decision for Liverpool as the manager continues to juggle a growing injury list ahead of Saturday's Premier League clash with Wolves at Anfield.
Mikel Arteta has backed Gabriel Jesus to make a major impact for Arsenal as the Brazilian prepared to start his first match in almost a year.
Tim Iroegbunam has said he is determined to seize his opportunity after being handed a rare run in Everton's midfield as David Moyes deals with growing selection problems.
Mikel Arteta said Arsenal won because his players stayed fully focused on the single task of beating Everton on Saturday, insisting that discipline and concentration were the key reasons they returned to the top of the Premier League.
