Bayern president Franz Beckenbauer anticipates United being one of the clubs hoping to tie up Marco Reus' signature next summer.
According to reports, the 25 year old's release clause is set to drop to around €25 million at the end of the season. A staggeringly small fee in football's day and age for one of the most highly-rated players in the world.
Bayern have expressed interest in a deal to bring Reus to the Allianz Arena, however the player has reportedly turned down a contract from the Bundesliga champions already, this summer.
But with Beckenbauer's team failing to lure Reus, he fully expects the likes of United and Real to get involved in the transfer pursuit.
"I can imagine him at Bayern very well," he told German paper Bild.
"If you can get a player of his class, you need to try it. If he doesn't go to Bayern in 2015, he will probably go to another big club like Real Madrid or Manchester United.
"Dortmund will probably not be able to hold on to him. I can understand why Dortmund don't like discussion about Reus."
Reus missed out on a place in Germany's World Cup-winning squad this summer after sustaining a serious knee injury prior to the tournament.
Despite strong speculation, he is widely expected to stay at the Signal Iduna Park for the upcoming campaign.