The 25-year-old is on the verge of signing for Chicago Fire with various reports the deal could be done to allow him to play against Atlanta at the weekend.
The MLS transfer window shuts on Wednesday, May 4 with talks progressing. It would see the player join his local MLS side having been born near Chicago.
Mueller made the switch at the end of last year, joining from Orlando City, after agreeing to the move months prior, signing a long-term deal.
With impressive performances for Orlando across the previous two campaigns and two international appearances for the US, there was excitement around the signing and he was viewed as a coup. However, Mueller started just six games, making 15 appearances in total, scoring one goal.
Mueller will return to a league where his reputation is strong following his time with Orlando.