Manchester United manager Sir Alex Ferguson is said to have reached the decision to retire at the end of the season as early as February.
The Scot notified chief executive David Gill and owners the Glazer family, none of whom attempted to change his mind, according to The Telegraph.
Everton boss David Moyes is thought to be on the brink of joining United as Ferguson's successor, based on the recommendation of the 71-year-old.
Moyes is expected to be named as United's new manager within the next 24 hours.