The Chelsea defender was forced off at half-time in Les Bleus' 3-0 win against Yugoslavia in a friendly at the Stade de France.
"I suffered a small injury to the external ligament of my right knee," said Desailly.
"I am disappointed, especially because it was a friendly match. I will wait for the result of the scan and then return to London.
"I hope that this is not too serious because we are currently going through a good spell at Chelsea," he added on his personal website.
If Marcel is to be sidelined for the duration then it looks like John Terry will finally get the place he has so patiently been waiting for.
stevefurlong@chelsea-mad.co.uk