United coach has been in touch with striker
The Uruguay striker has been in impressive form at the World Cup finals in South Africa, netting three goals as he helped his country to a place in the semi-finals.
Forlan currently plays for Spanish side Atletico Madrid, after two unsuccessful years at United saw him move on from the Premier League club.
The 31-year-old managed just 10 league goals during his time at Old Trafford, but the front man has since transformed his career in La Liga.
A successful spell at Villarreal earned a move to Atletico, who he helped guide to Europa League glory this season, seeing off Fulham in the final.
The revival of Forlan on the world stage has led many to wonder what went wrong whilst under Sir Alex Ferguson's stewardship.
But one of United's backroom staff - Rene Meulensteen - says the problem was the timing of the move for the player.
And the Dutchman revealed he would happily see the former Independiente man back in a Red Devils jersey on his current form.
Meulensteen told Voetbal International: "Diego was at the wrong place at the wrong time. But we had some individual training with Diego, for months we worked hard.
"I told him, 'what you learn here, you will take with you'. You are a player who adds something to every squad.
"He has developed fantastically, so complete - a top athlete. I really would welcome him back to Manchester United."
Meulensteen said he sent Forlan a text message after he netted both goals in the victory over Fulham, reading: "Top class, if it's up to me you will return to us."
The striker reportedly replied: "I am ready for it."