Everton midfielder Marouane Fellaini will be out for three weeks with a knee injury, according to the Belgian Football Association.
It now looks certain Fellaini will miss the first Merseyside derby of the new season - at Goodison Park on October 28.
The 24-year-old, who's netted for Everton three times, picked up the knock in Saturday's Barclays Premier League game against Wigan, but nevertheless travelled to meet up with his national team who face matches against Serbia and Scotland in the coming days.
A scan has shown the injury is worse than first thought, though, and he now faces a period on the sidelines.
A statement on the Belgian FA's website read: "Fellaini suffered a small tear at the juncture of muscle and tendon in the knee. The injury was revealed during a scan.
"Fellaini was injured last Saturday during the match between his club Everton and Wigan Athletic. He will be out three weeks.
"It has been agreed with his club Everton FC he will rehabilitate in Belgium during this period."
Everton have not yet commented on the announcement.