The 19-year-old defender is set to undergo a medical in France on Monday afternoon ahead of a €10 million [£8m] switch to the Ligue 1 club from BotafogoBotafogo defender Doria looks to be on the verge of a switch to Marseille, with the youngster set to undergo a medical in France on Monday afternoon.
The highly-rated 19-year-old centre back has been persistently linked with a move to Europe this summer and speculation has increased with Botafogo in the midst of a financial crisis that has seen a number of players go without wages.
And Vagner Mancini says the stopper, who was also attracting major interest from Lyon, Lazio and Valencia, will be sorely missed by the Rio de Janeiro club.
"He's a spectacular athlete, he's so much more than everybody thinks," Mancini told a press conference on Sunday.
"He'll be soon be playing for Brazil. I am sorry he's leaving, we'll miss him very much. He's an unique talent. I wish him luck for his future career."
The under-20 international has made one appearance for the senior national team, appearing against Bolivia last year in a friendly for domestic-based players only.
He will cost the Ligue 1 club a fee in the region of €10 million [£8m], of which around Botafogo will receive €3m [£2.4m] for the 30 per cent stake they hold in his registration.