The pair are together this month for Brazil's Olympics campaign.
Rafael when asked after Brazil’s 2-0 win over Great Britain whether attacking midfielder Lucas, who also played in the game, was excited at the prospect of joining United, he replied: “Yes, yes!”
He added: “And yes, I have told Lucas he should come to Manchester United - of course.
“If you saw the way we played at Middlesbrough you will know Brazilian players can play well in England! We enjoyed the game, but we just enjoy playing.
“I have heard about Oscar coming to Chelsea and he is a good player and very important for us. I really think he will do very well in the Premier League because he is a talented player.”