MESA, Ariz. — As Mike Fiers took the field to prepare for Sunday’s game, he was greeted with cheers and even signs supporting his actions as the lone public whistle-blower in the Astros cheating scandal.

“One of them said, ‘Mike Fiers for President!’” the A’s pitcher said. “It’s always good to see positive responses. ... That always makes you feel better.”

Fans at the A’s game against the Giants at Hohokam Stadium gave Fiers sustained applause when he was announced as the starting pitcher and again when he took the mound for his scoreless two-inning stint.

“I totally support what Mike did, and so do all the other fans I know,” said Jonathan Espinosa, 32, of Oakland. “It’s not fair, a team gets away with cheating and nothing happened until he said something. No one else put their name on it — that’s sticking your neck on the line for the game to be cleaned up.

“When he walked out today, we were all saying, ‘Hey, Mike, we’re behind you!’ and I yelled, ‘Mike, we’ve got your back!’”

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“I told him, ‘Mike, you did the right thing,’” said Eric Robles, 30, of Mesa. “For the most part, he’s going to get a warm reception wherever he goes except Houston.”

Oscar Gonzalez, 37, of Oakland said he considers Fiers a good role model for children, unlike one of his former favorite Astros, whom he compared to one of baseball’s players most connected to steroids. “I’ve lost my respect for Jose Altuve,” Gonzalez said. “He’s got an asterisk now. As far as I’m concerned, he’s just like Barry Bonds. But Mike is standing up for what he believes.

“And he’s going to hear it in Houston. His first start there is going to be bad.”

Fiers has faced significant backlash and even threats for his actions. Former players David Ortiz and Pedro Martinez have criticized him for “snitching” on the Astros.

“I know people are calling him a snitch but no one else there was willing to say anything, and what Mike did ultimately is good for baseball,” said Brandon Kuhn, 28, of Tucson. “He got by far the biggest applause of anyone today, it’s obvious how much everyone supports him.”

“Mike looks ready to go and focused — and he’s a hero in Oakland for coming out and doing what he did,” said Tyler Morrison, 25, of Gilbert, Ariz.

Tina and Rick Minkkinen came to Mesa from Fresno for three days and were delighted to find out that Fiers was on the mound Sunday.

“I was excited because I want to support him,” said Tina, 54. “For me, Mike fixed the integrity of the game. He did something most people wouldn’t do, and I’m so happy to see the ovation he got.”

A’s players also took note of how much goodwill there was toward Fiers at Hohokam, but for them his two hitless innings, with one strikeout, were even better.

“Classic Mike Fiers,” first baseman Matt Olson said. “Under 90 mph the whole time and getting outs. A guy who just knows what he’s out there to do.”

Manager Bob Melvin said Fiers looked “really good” and efficient, using all of his pitches, and he particularly liked Fiers’ changeup. “Nice ovation, too,” Melvin said. “Not a surprise. Our fans know what he’s going through. They’re very aware.”

“I loved it,” reliever Jake Diekman said of the crowd reception. “And Mike dealt.”

Susan Slusser is a San Francisco Chronicle staff writer. Email: sslusser@sfchronicle.com Twitter: @susanslusser