McDermott, 52, has left the club after less than a year in charge following a turbulent week in which his authority appears to have been undermined by takeover talks with Italian Massimo Cellino..
Results have not helped McDermott’s cause with Leeds failing to win in their last eight matches, a run that has included the 6-0 thrashing at Sheffield Wednesday and an embarrassing FA Cup exit at the hands of Rochdale.
The takeover of the club is thought to be nearing completion with Cellino preparing to complete a 75 per cent purchase of United from Gulf Finance House.
It is thought Festa is the Italian’s first choice to replace McDermott as manager after he was seen at the training ground this week.
Gianfranco Zola is second favourite to be the new manager, but whoever takes over could face a problem straight away with star striker Ross McCormack now looking like he could follow McDermott out of the door.
McCormack appeared to open the door to a move, hours after pledging his future to Leeds and McDermott in particular.
He said: “The club have decided to sack him, unfortunately. He called me up earlier and told me he was gone.
“It’s hard times at the club. I’m absolutely gutted because I had a really close relationship with the manager.
“I’m very happy and content at the club, but I think a big part of that was Brian McDermott. At the moment it is still very raw and I’m gutted.
“There are three hours left [of the transfer window] and I can’t see anything happening. Whether that changes, we will see. I’m lost for words, I can’t believe what’s happened [to McDermott.”
Leeds United have yet to put out an official statement on McDermott’s departure or who made the decision to sack him.