Di Matteo said: “My first feeling is of disappointment but in general for the sake of the player they need to learn about what it takes to be an athlete.
“He needs to grow up very quickly. It’s not the first time and he needs to understand that if he wants a good career he has to stop.”
The Villa boss added: “The investigation is ongoing. Once we finish and have all the facts then we will take whatever action is deemed necessary.”