Fifa confirmed on Tuesday night that it was awaiting documentation from Fiorentina.
Fornasier has been offered a contract by United after impressing while playing for the club in the Milk Cup this summer.
Fiorentina were unable to sign Fornasier to a contract before his 16th birthday. due to Italian law.
The grounds for the Viola’s complaint to Fifa remain unclear.
“We can confirm that we were contacted by Fiorentina with regard to the potential transfer of the player, Michele Fornasier, to the English club, Manchester United,” a Fifa spokesman confirmed.
“However, so far no formal investigation was opened since the relevant documentation needs to be completed.”
