After their 1-1 draw at Leeds United, Amorim let loose on the club's top brass, hinting at broken promises over his role within the management structure.
He said in part: "I just want to say that I came here to be the manager of Manchester United, not to be the coach.
"And every department, the scouting department, the sports director needs to do their job. I will do mine for 18 months and then we move on."
Despite his blast for the higher ups, United insiders insist the decision to remove Amorim had nothing to do with his rant.
Instead, speaking to BBC Sport, one source said "that the club felt there had not been sufficient evidence of evolution or progress this season under Amorim".
United are currently sixth on the Premier League table and three points off a Champions League place having won one and drawn two of their past three games.