The former Swindon Town manager watched from the directors' box at the Madejski Stadium as Reading suffered a 2-1 defeat against fellow strugglers Aston Villa on Saturday.
McDermott's departure on Tuesday prompted further claims that Di Canio could take charge of the Royals, but the Italian insisted too much was being read into his appearance at the game.
"It was just a coincidence. I was there only to watch the game," he said.
"I was sat with Stuart Pearce at Reading and we had some discussions about the game.
"I want to watch games at the top level and [the Madejski Stadium] was full of passion, so it was good to go there.
"Next time it could be Swansea or Southampton or Tottenham, I don't know, but this is what I am going to do for the next few weeks."