At a rally on Aug. 19 at the downtown minor league baseball stadium, about 1,400 fans watched as M.L.S. Commissioner Don Garber confirmed that Minnesota United would begin play in 2017.

“I’m glad somebody who’s strictly going to focus on soccer is going to keep a team in the Twin Cities and push it as high as it can go,” said Bruce McGuire, a Minnesota soccer blogger and scarf-wearing member of the United’s primary fan group, the Dark Clouds. “It’s thrilling,” said McGuire, who is not related to the team’s owner.

The bid by the Vikings owners, Bruce McGuire said, “scared the hell out of me.”

“The sport I love would be a second priority,” McGuire said. “The N.F.L. is a gold mine, and everything else has to be second.”

William McGuire, too, feared that the Vikings group would land the franchise.

“There was always a chance the league would look at that situation and say, ‘This is what we want to do,’” said William McGuire, who is widely known as Bill. “We didn’t think it was the right thing to do. Obviously, we had our own bias. Our view was, the best thing for soccer is to have soccer-specific stadiums, if it could be pulled off, rather than putting the sport into a stadium that’s fundamentally built for something else.”