Jonathon P. Feyereisen (born February 7, 1993) is an American professional baseball pitcher in the Milwaukee Brewers organization. He was drafted by the Cleveland Indians in the 16th round of the 2014 Major League Baseball Draft.
Feyereisen attended River Falls High School in River Falls, Wisconsin and played college baseball at the University of Wisconsin at Stevens Point, and summer collegiate baseball with the Wisconsin Rapids Rafters. He was drafted by the Cleveland Indians in the 16th round of the 2014 Major League Baseball Draft. He signed with the Indians and was assigned to the Mahoning Valley Scrappers, where he spent the whole season, pitching 17 scoreless innings, striking out 24. In 2015, he played for both the Lake County Captains and the Lynchburg Hillcats, posting a combined 1–1 record with 12 saves and a 2.08 ERA in 47 ⁄3 innings in which he struck out 56 batters between the two teams. He began 2016 with the Akron RubberDucks.
On July 31, 2016, the Indians traded Feyereisen along with Clint Frazier, Justus Sheffield, and Ben Heller to the New York Yankees in exchange for Andrew Miller. The Yankees assigned him to the Trenton Thunder where he finished the season. In 42 games between both Akron and Trenton, he pitched to a 7–3 record, five saves, 1.70 ERA, and a 1.10 WHIP as he had 78 strikeouts in 58.1 innings.
Feyereisen spent 2017 with both Trenton and the Scranton/Wilkes-Barre RailRiders, posting a combined 2–3 record with four saves and a 3.27 ERA in 63 ⁄3 total innings between both clubs. He spent the 2018 season with Scranton/Wilkes-Barre, going 6–6 with one save and a 3.45 ERA in 60 innings. He returned to Scranton/Wilkes-Barre for the 2019 season, going 10–2 with seven saves and a 2.49 ERA and 94 strikeouts in 61 innings.
On September 2, 2019, Feyereisen was traded to the Milwaukee Brewers in exchange for Brenny Escanio and international signing bonus pool money. He pitched for the United States national baseball team in the 2019 WBSC Premier 12 tournament in November 2019. Feyereisen was added to the Brewers 40-man roster following the 2019 season.