Other clubs are also believed to be interested in the £7m-rated Brazilian, but he has given United the go-ahead to make a bid by indicating that they would be his first-choice destination, above even Los Blancos.
"Yes, I would prefer that [to join Manchester United]," he told reporters. "The structure they have in place is one of the best in the world. I have been there already and went to a lecture by [Sir] Alex Ferguson when I was younger.
"I feel I am ready to play in any part of the world. If you play for Cruzeiro, you can play in any place. I would fit in any part of the midfield. I would do well as a playmaker to support the attack."
Ribeiro, 24, recently helped Cruzeiro to win the Brazilian title for the first time in 10 years.