Louis van Gaal made the decision not to sign Radamel Falcao following the FA Cup win over Preston North End.
The Colombian striker has failed to adapt to life in the Premier League after joining United last summer on a one-year loan from Ligue 1 side Monaco.
Having scored goals in Portugal, Spain and France during his career, the former Atletico Madrid striker was tipped to secure a permanent move to Old Trafford this coming summer, with a £43m clause included in his loan deal.
However, the 29-year-old will now return to Monaco, according to L’Equipe.
Van Gaal has so far refused to publicly discuss the matter regarding his future, but it is understood that he was angry at Falcao’s performance against League One side Preston last month and has since made a decision not to sign the striker.
The likes of Atletico Madrid and Valencia have been interested.