The Belgian duo Romelu Lukaku and Eden Hazard will miss the play-off for third place in the Nations League with Italy due to “muscle overload”.
Chelsea striker Lukaku will initially be returning to Belgium from Italy rather than London and manager Roberto Martinez doesn’t know when he will be fit.
Lukaku played the entire 3-2 semi-final defeat against France on Thursday and scored one goal.
“They don’t have the best conditions to play,” said Martinez of Lukaku and Eden Hazard of Real Madrid.
“They are leaving the national team camp because of these problems – I don’t know how long it will take them to recover.”
He said there would be no problem with Chelsea if Lukaku went to Belgium instead of going straight back to his club team.
“Obviously there is an excellent understanding between the two medical teams and we want to do our best for the player,” he added.
“Every decision is made in agreement with the club.”
Chelsea visits Brentford next Saturday (5:30 p.m. BST).