Isak, who scored only his second Premier League goal of the season on Saturday in 10 appearances, has struggled since arriving at Anfield.
Earlier this summer, he was left out of the Newcastle squad for their pre-season tour of Asia with what the club described as a “minor thigh injury”, while it was understood he wanted to explore a move away.
Isak then trained alone at his former club Real Sociedad before joining Liverpool on deadline day.
Without a proper pre-season, he arrived short of match fitness and has started just 10 times in all competitions.
Liverpool are also without Mohamed Salah, who is with Egypt at the Africa Cup of Nations, and the injured Cody Gakpo.
Fellow forward Hugo Ekitike, who joined in the summer from Eintracht Frankfurt, was also on target at Spurs and expected to continue to lead the line for the Reds.
The 23-year-old Frenchman has scored 11 times this term, with five in the last three league games a factor in Isak starting on the bench.