The news adds to the perception that Briton Hamilton - who was nurtured through his formative years by the McLaren supremo and brought into F1 in 2007 - has fallen out badly with Dennis over the 27-year-old's Mercedes switch.
But after Hamilton won the US Grand Prix, Dennis refused to wear McLaren's customary 'rocket-red' victory t-shirt.
And the 65-year-old "has decided not to travel to Sao Paulo for Hamilton's farewell race", McEvoy revealed.
Dennis said in Austin last week: "Obviously the media thinks there's some issue between Lewis and I -- there's absolutely no issue between us.
"Sometimes the circumstances in a relationship don't balance, don't match," he told the British broadcaster Sky.
But there are rumours Hamilton and Dennis fell out very badly over the negotiations for a new driving contract for 2013 and beyond.
"I do know what has happened," an unnamed 'senior figure' told the Daily Mail.
"Everyone makes mistakes and Ron made a mistake. Everything went pear-shaped and I don't think it would be fair to say any more than that."
A McLaren spokesman responded: "Ron and Lewis plan to get together socially in the near future, as they've both said a number of times recently."