Manchester United midfielder Ander Herrera could be out for several weeks after fracturing a rib in Saturday's 2-1 victory over West Ham.
The 25-year-old, who joined United from Athletic Bilbao in the summer, has scored twice in four Premier League appearances for Louis van Gaal's side.
He joins a 10-strong Old Trafford injury list, which includes Michael Carrick, Phil Jones and Ashley Young.
Captain Wayne Rooney is also suspended for the next three matches.
Herrera was substituted in the 74th minute of the victory over West Ham and no time limit has been put on his absence.
A statement on United's website read: "The club will continue to monitor his progress over the next few weeks."
United face Everton on Sunday and, after a two-week international break, they then face West Brom, Chelsea and Manchester City.