According to ESPN, United will make a move for the Germany international forward and will make a bid of £30 million.
Fjortoft, a former Middlesbrough and Sheffield United forward, does not believe that Muller will switch to United.
Re: Müller to Man UTD My source tells me: - Dont think so, but you never know. Will be a crazy summer #MUFC— Jan Aage Fjortoft (@JanAageFjortoft) May 17, 2015
Muller is one of the best players in the world, and it comes as no surprise that United are interested in him.
Red Devils boss Louis van Gaal has worked with the 25-year-old during his time as coach at Bayern and knows all about the German star.
However, it will not be easy for United to convince Bayern to sell Muller, whose contract with the Bundesliga outfit runs until June 2019.
Muller has scored 13 goals and created 39 chances in 31 Bundesliga appearances this season, while having a pass accuracy of 72% and a shot accuracy of 62%.