The Italy midfielder collided with intercoach Simone Inzaghi after their final of the Champions League by PSG.
Fratteni stayed behind on the couch when interning 5-0 in Munich collapsed and he confronted Inzaghi after the last whistle, says La Gazzetta Dello Sport.
If Inzaghi is confirmed for next season, Frattesi will look for a move.
The 25-year-old is on a contract with Inter that extends until the summer of 2028.
The midfielder is connected this season to Napoli and former Club Roma.