According to a report by Brian Quarstad and Alex Schieferdecker at Northern Pitch, Minnesota United FC has secured a stadium site, and has Major League Soccer's backing for an MLS franchise. Sources indicate that team owner Dr. Bill McGuire has secured an option to purchase land near the Minneapolis Farmer's Market, near Target Field, and that the league has provided written support for the stadium effort. 

It would appear that the only hurdle remaining is the details of financing the franchise fee and stadium construction, and it's unlikely that United and MLS would move this far along without having at least the framework of a deal in place.

More details are available at Northern Pitch, but the key quote is this: "Multiple sources suggest an announcement of an agreement to bring United into MLS could come within the next month."