Leicester City midfielder Wilfred Ndidi has been ruled out for three months with a muscle injury.
The 27-year-old missed the Foxes’ Championship win over Huddersfield on New Year’s Day and was then replaced in Nigeria’s 2023 Africa Cup of Nations squad on Wednesday.
A three-month absence could see Ndidi miss 15 of Leicester’s remaining 20 league games this season.
“For Wilf, it will be a long time,” said Foxes boss Enzo Maresca.
“It could be three months. It looks like a muscle problem, but an important one so we now see in the next hours.”
Ndidi, an FA Cup winner with Leicester who is into the final six months of his contract at the King Power Stadium, has been a key member of Maresca’s table-topping Foxes.
He has made 24 appearances in all competitions, scoring four goals and providing six assists.
Last Wednesday, Ndidi was ruled out of Nigeria’s 2023 Africa Cup of Nations campaign because of injury.
The 27-year-old Leicester City midfielder was named in the Super Eagles’ 25-man squad on 29 December but was absent from his club side’s win over Huddersfield Town on Monday.
Royal Antwerp midfielder Alhassan Yusuf has been called up to replace Ndidi.
Nigeria are still hopeful Ndidi’s Leicester team-mate Kelechi Iheanacho will be able to join the squad.
Forward Iheanacho, 27, has missed the Foxes’ past two games in the Championship with a muscle problem.
Nigeria begin their Group A campaign against Equatorial Guinea on 14 January, and the West Africans will also face hosts Ivory Coast and Guinea-Bissau in the group stage.