Photographs of the player - posted on his own Twitter account - have gone viral with many suggesting Minala is nowhere near his supposed age of 17.
Senego.net claims Minala confessed that he will turn 42 in August and lied about his age in order to send money home to his family in Cameroon.
"The thing that surprises me is that there are some sites, who have no credibility, don't verify information before publishing it," agent Diego Tavano told TMW.
"It is disconcerting that someone is playing on this story. The lad is relaxed anyway, as perhaps those spreading these rumours are the classic fox who couldn't reach the grapes...
"Joseph has talent, he is 17 years old and the Tribunal in Rome verified it. It's remarkable some claims are given credence."