West Ham United defender Angelo Ogbonna damaged knee ligaments during Sunday’s 3-2 Premier League win against Liverpool.
Ogbonna, 33, was forced off with an eye injury during the first half but later complained of discomfort in his knee.
A scan on Monday showed the Italy centre-back had damaged his anterior cruciate ligament.
Reports say he will see a specialist later this week to determine whether he needs an operation and a timescale of recovery.
Ogbonna has started all of West Ham’s Premier League games this season, with a goal to his name.
The Hammers rose to third in the table after their victory against Liverpool at London Stadium.
David Moyes’ side are also through to the EFL Cup quarter-finals and have qualified for the Europa League knockout stages with two group games to spare.