The 19-year-old midfielder on Monday said that he was willing to play in Europe while United's delegation had arrived in Brazil on Tuesday after Lucas' father, who is also his agent, spoke to Inter Milan on Friday.
However, despite the talks between Inter and Sau Paulo, director of football Joao Paulo de Jesus Lopes slammed Inter's £20 million bid as an 'ridiculous' offer.
"How can you pay €25 million (£20 million) for a player of Lucas's quality? There is no offer and, even if it were to appear, this amount is ridiculous," Jesus Lopes is quoted as saying in the Daily Mail.
"Italian football is broke, the club (Inter) are broke. It seems they are creating this to satisfy the fans," he added.
Lucas' father had previously hinted a move to real Madrid but they have switched to players like Luka Modric and David Silva. Chelsea's €32m had been rejected but they have now agreed terms with Internacional's Oscar while Inter Milan's €20m was also rejected.
"I cannot guarantee that I will stay until the end of my contract," Lucas said. "Much has changed and the situation is not up to me any more. I know my father and my agent had a meeting (with Inter) but I don't know what was said. Now I will go to the Olympics with my mind only on winning a gold medal," he added.
"When I go on the internet I see Inter, Real Madrid and I don't know who else, wanting to come for me with a truck load of money. Of course I think about it, but I can't let it go to my head. I'm very calm and down to earth about it. My job is to play football so that these clubs continue to be interested," he said.
Manchester United were heavily linked with a €40m bid for Inter Milan midfielder Wesley Sneijder during the January transfer window last season. Porto star Joao Moutinho, who shined at the Euro 2012 for Portugal, has been linked with a switch to Old Trafford for a fee worth €30 million.