Crystal Palace midfielder Adlene Guedioura has been ruled out for at least six weeks with a punctured lung and two broken ribs.
Guedioura, 27, was carried off on a stretcher after colliding with West Bromwich Albion goalkeeper Boaz Myhill during Palace's 2-0 defeat on Saturday.
"It doesn't look good for him," said Palace caretaker-manager Keith Millen.
"The trouble with cracked ribs is that you can't exercise and you can't get your heart and lungs going."
Millen added: "Some injuries, you can keep your cardiovascular fitness up but with this injury you can't do anything."
Algerian international Guedioura joined Palace from Nottingham Forest at the end of the summer transfer window and has made four appearances this season.