Oakland Athletics fan K.C. Sandstrom was sitting down the right field line watching his team warm up while armed with a small dry-erase board, a marker and a statement written in all caps.

“MIKE FIERS FOR PRESIDENT”

It's been a tumultuous few months for Fiers, the current A's pitcher and former Houston player who helped expose the Astros' sign-stealing scandal that's rocked Major League Baseball. But on a cool Sunday in Arizona, the 34-year-old received a largely warm reception during his first spring training appearance in Mesa.

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“Oakland's going to support us no matter what," Fiers said after throwing two perfect innings against San Francisco. “They've always been there. It's fun, it's fun playing in front of these fans and with these guys. Just a great day of baseball.”

While Fiers is now widely known for his connection to the Astros' sign-stealing, he's also an accomplished pitcher. He's thrown two no-hitters over nine seasons and is coming off his best year in the big leagues — he finished with a 15-4 record and 3.90 ERA in a career-high 184 2/3 innings in 2019.

He's expected to have a prominent role on this year's staff as well.

The right-hander had a good start to spring, retiring all six of the Giants he faced. When the Oakland lineup was announced before the game, he received loud cheers from the A's side of the stadium. The Giants' side was a little less enthusiastic, but certainly not hostile.

“Overall, a good day,” Fiers said. “I was able to throw strikes, I was able to put balls where I wanted to and threw all my pitches.”

Baseball's biggest scandal in years began in November after Fiers detailed to The Athletic about how the Astros used electronics to illicitly steal signs from opposing catchers during their World Series-winning season in 2017. Fiers pitched three seasons for the Astros, including 2017.

The fallout — for the Astros, Fiers and the entire sport — has been even more intense than many anticipated.

An MLB investigation led to a season-long suspension for Houston's general manager Jeff Luhnow and manager AJ Hinch and both were fired by Astros owner Jim Crane. Boston Red Sox manager Alex Cora and New York Mets manager Carlos Beltrán — who were both part of the Astros in 2017 — were also fired by their respective teams.

No players were disciplined, but the Astros have received a torrent of criticism from stars such as Mike Trout, Cody Bellinger and Aaron Judge, and fans all over.

Houston outfielder Josh Reddick said on Friday that he and other players have even received death threats in response to the scandal. Fiers said he'd also gotten them.

The Astros were met with a hostile reception during their spring training opener against the Washington Nationals on Saturday. Fiers avoided the same kind of response on Sunday in front of a friendly crowd.

Fiers' role as the whistleblower in the Astros' scandal has been met with both praise and criticism. Commissioner Rob Manfred said on Tuesday that the sport would "take every possible step to protect Mike Fiers wherever he's playing, whether it's in Houston or somewhere else” and added that “Mike did the industry a service."

Others haven't been as complimentary. Former Boston Red Sox slugger David Ortiz said Fiers was “looking like a snitch” for disclosing the team's cheating scandal only after he had left the team.

Fiers said everyone is entitled to their opinion and he wasn't concerned.

“It's all about going out there and playing baseball for everybody," Fiers said. “Every team's trying to get back out there, play the game we love and compete. The rest will take care of itself.”