The much-ballyhooed return of Michael McDonald to the Doobie Brothers after 26 years got short-circuited Tuesday due to what a band member indicated was a case of COVID-19.

The Minnesota State Fair announced late Tuesday afternoon that McDonald would not perform Tuesday evening but the rest of the Doobies would.

The opening act, Dirty Dozen Brass Band, also canceled. The fair did not offer an explanation for the change in the lineup.

After the second song on Tuesday night, co-founder Patrick Simmons, a singer/guitarist, said McDonald was not feeling well.

"He's recuperating and isolating. We hope to have him back in a week or so," he said, adding that it's what's happening these days.

"He's had his vaccine," Simmons said. "But the show must go on."

The Doobies entourage is traveling with a COVID compliance officer. All the band members and crew are vaccinated, co-founder Tom Johnston, also a singer/guitarist, told the Star Tribune last week.

"If you weren't singing [in rehearsals], you had to have a mask on. Everybody in the crew has to have a mask on," he said.

"Having had [COVID] once myself, it makes you think about it. It depends on where you're playing. Various areas of the country go up and down as far as the intensity and shall I say 'risk' there is, for lack of a better word."

Backstage on Tuesday night, everyone was wearing masks. More people in the crowd were wearing masks than it appeared at any other State Fair concert.

After an 18-month delay, the Doobie Brothers kicked off their 50th anniversary tour on Aug. 22 at the Iowa State Fair. The Minnesota State Fair is the sixth stop on the tour. McDonald has participated in the previous shows in Iowa, Wisconsin and Illinois; three of them were outdoor venues.

The concert at the Minnesota State Fair grandstand was sold out. To inquire about refunds, e-mail the State Fair ticket office at tickets@mnstatefair.org.

Twitter: @JonBream • 612-673-1719