Manchester City striker Mario Balotelli was caught throwing darts towards a group of youth team players at the club's training ground on Sunday.
The incident comes just days after Balotelli asked Italy boss Cesare Prandelli for help to change his errant ways, which have recently irked his club manager Roberto Mancini.
Balotelli was excluded from Prandelli's latest Italy squad after he received a red card for a Nigel De Jong style challenge on a Dynamo Kiev player in the Europa League.
Prandelli has implemented an ethical code since taking charge of Italy and expects his players to behave well even when they are not on international duty.
Balotelli is quoted as telling several newspapers that he threw the darts because he was bored.
City aren't said to be treating it as a 'serious transgression' but rather as a 'misguided prank'.