British newspapers on Friday reported that Tan had ordered Mackay to resign, or be sacked, due to the owner's disappointment with several aspects of his management.
Mackay, who has taken the club into the top flight of English football for the first time in more than half a century, was due to hold a routine televised news conference to preview Saturday's match against Liverpool but instead assistant manager David Kerslake was parachuted in the chair.
Kerslake, clearly uncomfortable, stumblingly answered a series of questions by repeatedly saying: "All I am here to do is talk about the Liverpool match."
A club official then stepped in to say "Malky is unavailable", though he refused to say why. He also declined to answer when asked if Mackay was still the manager.
Despite the chaos swirling around the club Kerslake tried desperately to present the party line.
"Everything's been normal," he said. "We've prepared as usual... I honestly don't think this affects the players."
Cardiff officials had banned journalists from tweeting from the news conference and also instructed Sky Sports TV personnel to dismantle their cameras from the car park of the hotel where the news conference was being held.
(Reporting by Mitch Phillips; Editing by John O'Brien)
