He has been usurped in the pecking order by Robin van Persie and clearly feels his future does not lie in the attacking midfield role he inhabited for most of last term.
After a game in May, former United manager Sir Alex Ferguson told the BBC "I don't think Wayne was keen to play, simply because he has asked for a transfer."
Should the English forward decide to leave, fans will want the money from his sale reinvested in new players in the transfer market.
Here are five potential alternatives. Make of them what you will.
It seemed for all the world that Borussia Dortmund striker Robert Lewandowski was set for a move to Bayern Munich.
The Poland international had a terrific 2012/13 season at the Bundesliga club, scoring 36 goals in all competitions.
But according to Dortmund president Hans-Joachim Watzke, the move is a dead one.
"Lewandowski will definitely not go to Bayern in 2013," he told Bild (h/t The Telegraph).
The hitman is a prolific goalscoring threat in the box and possesses excellent creativity out of it. It would take a shift in tactics from David Moyes to get him working efficiently with Van Persie next season, though.
Perhaps Manchester United fans were being too optimistic in the hope that Cristiano Ronaldo would return to Old Trafford this summer.
He seemed unsettled at the Bernabeu for much of last season, though this may have been due to his awkward relationship with former boss Jose Mourinho.
Real remain committed to keeping him in Spain. In a recent interview with Marca, club president Florentino Perez said "To renew Cristiano before the start of the season is my desire and my ambition" (h/t The Sun).
There is still a glimmer of hope that the Red Devils can pull off one of the greatest coups of all time, but it is fading quickly.
£65 million is the touted price tag, but that's if Ronaldo demands to leave.
This one might be a little out of left field: Atletico Mineiro's Bernard.
The attacking midfielder is a highly promising Brazilian prodigy who has already been capped by the national team at the age of 20.
He is a lightning-quick, tricky playmaker who is also adept at finding the back of the net. At 5'4", he may need time to adapt to the Premier League, though.
His price tag is in the £10-15 million range.
Stevan Jovetic is one of the hottest names on the transfer market this summer.
The Fiorentina forward has had an excellent campaign in Serie A, leading his team to European qualification.
Jovetic could easily play the second-forward role behind Van Persie. It would cost the Red Devils around £25 million to get him, though.
Gareth Bale could potentially break the world record £80 million transfer fee paid for Cristiano Ronaldo's services by Real Madrid.
His worth is estimated to be £85 million by some sources. That is a staggering amount, and it reflects the financial nature of today's game.
Earlier this week, The Sun reported that "[Real] will not baulk if Tottenham demand £85million for Gareth Bale."
Club president Florentino Perez told Marca: "For those players and investments that generate and produce income, you can give everything in life."
Would Bale be worth the Red Devils "giving everything in life?"
Who else could be an alternative to Wayne Rooney, were he to leave?