The plan to leave the Trafford club came into limelight after Rooney showed his desire not to extend his contract and the report was confirmed by team manager Alex Ferguson.
"We just don't know what's changed the boy's mind... I was shocked," Ferguson said. "I had a meeting with the boy and he reiterated what his agent had said. He wanted to go."
Though Barcelona tries to grab the striker, sources said he is also interested in Manchester City, Chelsea and Real Madrid, who want the united's striker don their colours.
Further reports said Chelsea has emerged as a potential bidder after manager Carlo Ancelotti said he would be interested in signing the England striker.
Rooney has become most marketable asset at United since the acquisition of Portugal forward Cristiano Ronaldo by Real Madrid for 5 million in Jun 2009 and Carlos Tevez who left the 18-time champions in United and joined Manchester City.