Stumpf played
college baseball at
San Jacinto College. He was drafted by the
Kansas City Royals in the 9th round of the
2012 Major League Baseball draft.
Philadelphia Phillies 2016 Stumpf was selected by the
Philadelphia Phillies in the 2015
Rule 5 draft. Stumpf made the Phillies' 2016
Opening Day roster, and debuted in the major leagues on April 7. On April 14, 2016, Stumpf received an 80-game suspension from Major League Baseball for testing positive for having used the
performance enhancing drug dehydrochlormethyltestosterone. He was designated for assignment by the Phillies on July 22. He was returned to the Royals three days later.
Detroit Tigers 2017 On December 8, 2016, Stumpf was selected by the
Detroit Tigers in the 2016 Rule 5 draft. Because Stumpf had been selected in the Rule 5 draft and returned to the Royals once before, he was able to elect free agency after the Tigers placed him on waivers and he went unclaimed. On April 1, 2017, Stumpf signed a Major League contract with the Tigers and was added to the 40 man roster. On June 2, 2017, Stumpf was recalled by the Detroit Tigers. Prior to being recalled, he posted a 1–2 record, with a 3.38 ERA and 26 strikeouts in 21 innings for the
Triple-A Toledo Mud Hens. He made his Tiger debut in a June 3 game against the
Chicago White Sox, allowing one hit and striking out one batter. Stumpf pitched innings for the 2017 Tigers, striking out 33 and posting a 3.82 ERA.
2018 Stumpf began the 2018 season in the Tigers bullpen. He earned his first Major League win with a perfect innings of relief in a victory over the
Pittsburgh Pirates on April 25. In relief innings over the 2018 season, Stumpf pitched to a 4.93 ERA with 37 strikeouts.
2019 Stumpf began the 2019 season in the Tigers bullpen. He was optioned to Triple–A Toledo on July 24 to make room for the recall of
Drew VerHagen. Stumpf returned to the Tigers as a September call-up. He was used as a lefty specialist throughout the season, only pitching 29 innings in 48 games. Stumpf was outrighted off the Tigers roster and elected free agency on October 24, 2019. ==Pitching coach controversy==