The agent of Gremio starlet Douglas Costa fears the teenager could be priced out of a move to Manchester United.
The Premier League champions are keen on the 18-year-old, dubbed the new Ronaldinho, but Gremio want around £18m.
Costa's representative, Cesar Bottega, claims informal talks have been held but added: "I don't believe that they (Manchester United) will reach this figure.
"Right now, an offer might come in at a maximum of £6.7m. But this would not be enough for [Gremio] president Duda Kroeff."