Petersen was an outstanding pitcher for the Bearcats from 1930 through 1932. He threw a total of three perfect games, including one on May 21, 1931 in which he struck out 15 batters. During the best-of-three NWC championship series in 1931, he won the first game and the third game, while recording a total of 32 strikeouts.

His single-game high for strikeouts was 23 against Oregon State early in the 1932 season. He struck out 18 batters the following weekend against Puget Sound. He left Willamette following the 1932 season.

He played in a series of games at Meiji Jingu Stadium in Japan during a tour of U.S. athletes. While in Japan, he hit a home run to center field that went farther than plaques marking the landing spots of homers hit by New York Yankee greats Babe Ruth and Lou Gehrig just a few weeks prior.

Petersen signed with the Yankees, but left several months later due to arm injuries. He went on to pitch for the Portland Beavers Triple-A team in 1934 before retiring from baseball in 1935. He was inducted into the NAIA District 2 Hall of Fame in 1965 and was selected for the McMinnville High School Hall of Fame in 2007.