The controversial striker has been in the spotlight again recently following his red card against Arsenal last weekend.
Theo van Seggelen, who is the general secretary of FIFPro, the world union of footballers, believes that the 21-year-old now needs help to make him understand his responsibilities.
"I think professional help is the only solution," Van Seggelen told BBC Sport. "I'm optimistic. I think he is a good guy but he has to change his behaviour for two reasons.
"First he is a role model, but also he is playing in a team and he is playing against another team and he has to respect his colleagues.
"I think that we have to realise and conclude that, after all these incidents, my personal opinion is that he needs, really, professional help."