The former Argentina head coach, who previously worked with Messi with the national team, believes that the Spanish club could one day be in a position to allow the 26-year-old to leave.
Maradona told Sport Bild: "Before, the power of the Barcelona members was so great that they didn't even allow sponsorship on the shirt. Now we see 'Qatar Airways' on the shirt. So if they allow advertising, why can't Messi play for Bayern Munich?
"I really believe that Messi could be wearing a different shirt now."
Messi's current deal with Barcelona expires in 2018.