FIFA could punish RB Leipzig striker Jean-Kevin Augustin after he rejected a France under-21 call-up by text message.
Augustin sent a message to U21 coach Sylvain Ripoll a day before he had been due to join the squad in which he said "muscle fatigue" meant he could not play.
Ripoll said that was not an acceptable excuse, but Leipzig counterpart Ralf Rangnick backed the 21-year-old forward.
Augustin, who has scored five times for his club this season, may face a ban from playing for them if FIFA's disciplinary commission finds he has infringed rules governing international breaks.
He wrote on Instagram that he had taken the decision not to play for the U21s "in consultation with my club" and that it could happen that "you have to deny yourself this honour in certain very special circumstances."
L'Equipe reported that the France Football Federation was keen to send a message to young players following Adrien Rabiot's refusal to be on standby for France's 2018 World Cup squad.
The under-21s won their two European U21 Championship qualifiers without Augustin to secure a place in the finals in Italy and San Marino next summer.