The 50-year-old was officially relieved of his duties yesterday morning, despite the fact that he was less than 12 months into the six-year contract that he signed upon his arrival last summer.
However, news of Moyes's departure was leaked to the media on Easter Monday, with the Scot thought to have been unaware of the speculation regarding his future at Old Trafford.
"Throughout his time at United, David, as he always does, has conducted himself with integrity and professionalism, values that he believes in and that have been strongly associated with the club and its rich tradition," said the LMA in a statement. "It is therefore sad to see the end of David's tenure at United being handled in an unprofessional manner."
Moyes has departed the 20-times champions of England with the club seventh in the Premier League.