On May 4, 2019, while pitching for Elon University, George Kirby did the unthinkable. He walked a batter. The walk was his first since April 14 and marked just his 6th and final walk of the 2019 season. Following the conclusion of his college career at Elon, the Mariners made Kirby their first round pick in the 2019 MLB Draft, selecting him 20th overall.
Upon joining the Mariners, Kirby made his professional debut with Short-A Everett, where he spent the remainder of the 2019 season. Between Everett and Elon, he tossed 111.1 combined innings in 2019, while issuing only 6 walks (0.