West Ham goalkeeper Lukasz Fabianski may require surgery after suffering a fractured cheekbone and eye socket.
The 37-year-old Poland international sustained the injury during Saturday’s 4-0 win over Nottingham Forest.
Manager David Moyes said he was unsure how long Fabianksi, who has started all 24 Premier League games this season, will be absent for.
“We don’t quite know whether it’ll be operated on or heal itself, or a time-span at the moment,” Moyes said.
Frenchman Alphonse Areola replaced Fabianski after 69 minutes at the weekend and is set to continue in goal for Wednesday’s FA Cup fifth-round tie against Manchester United.
The Hammers, who travel to Brighton in their next league match on Saturday, are 16th in the table – two points above the relegation places.