But will he yell "O" during the national anthem?
Arizona transplant and Baltimore native Michael Phelps will throw out the first pitch at Game 3 of the National League Division Series between the Arizona Diamondbacks and Los Angeles Dodgers in Phoenix on Monday night.
Phelps retweeted the Diamondbacks' announcement, saying, "Hope I make it over the plate!!"
The Olympic gold medalist and Orioles fan is no stranger to the baseball diamond. In 2003, he threw out the first pitch at an Orioles game to B.J. Surhoff. And in 2013, he took part in batting practice with the Orioles during spring training in Florida, where it was reported he had varying success.
Phelps showed his Baltimore sports pride too when he was on the medal stand receiving his 20th gold medal in the Summer Olympics last year in Rio. Someone in the crowd yelled out "O" during the national anthem as Baltimore fans do, causing Phelps to laugh. He later said, "Back in Maryland, we all say, 'O.'"
Phelps lives in Tempe, which is about a half-hour from Chase Field, home of the Diamondbacks, and is an assistant for the Arizona State University swim team, where his longtime coach Bob Bowman coaches.
The Diamondbacks trail the series, 0-2. The game will start at 10:08 p.m. and be broadcast on TBS.