The 24-year-old is widely regarded as one of the best defenders in the Campeonato Brasileiro, but has been identified by head coach Paulo Autuori as a player available for transfer, in a bid to ease Vasco's growing financial problems.
Red Devils boss Sir Alex Ferguson has been credited with an interest in bringing Dede to Old Trafford, but he will face competition for the South American's signature from Premier League rivals Liverpool, who are also in the market for a centre-back this summer.
With Jamie Carragher set to retire at the end of the season, Brendan Rodgers wants to strengthen his defensive options at Anfield, with some doubts still remaining over the long-term futures of Daniel Agger and Martin Skrtel.
"I know Dede is leaving, we talked about this since when I was negotiating with the club," Autuori confirmed. "I won't make up stories as that only complicates things."
Manchester United have strength in depth at the back, but with Rio Ferdinand yet to sign a new contract and rumours also linking Nemanja Vidic with a move away this summer, Ferguson might move for Dede when the transfer window reopens on July 1.
With six caps for Brazil's national team, the Vasco stopper clearly has plenty of pedigree, and at 6ft 4in tall would have no trouble making the transition to the physical nature of the Premier League.