The France attacker faces ten weeks out after suffering a thigh injury last week, amid claims he hasn't been behaving properly off the pitch.
But a club source insisted on RMC: "This relapse is so unfortunate. Ousmane has matured a lot, he is no longer the same. He changed and became professional.
"The critics are unfair and look for other problems.
"The training, because of the repetition of the matches, are quite light at the club and Ousmane is a victim of that too."