Although Keegan had initially committed to
Virginia Tech, he later committed to
Vanderbilt University when
Pat Mason, Virginia Tech's head baseball coach, was fired in May 2017. Keegan later committed to Vanderbilt by June 2017. In November 2019, Keegan suffered a
blood clot, necessitating surgery on November 16, and another later that month for internal bleeding. He said of the experience: "It was pretty scary, but I had a lot of help, a lot of support from coaches, teammates – my family." In the 2020 season, cancelled due to the
COVID-19 pandemic in the United States, Keegan appeared in nine games, making eight starts. He also returned to the CCBL, playing with the
Yarmouth-Dennis Red Sox. In 2022, his senior year, Keegan split his time between catching and first base, produced a .366 batting average (fifth in the Conference), and led the team with 12 home runs. He is a member of the First Team All-SEC and a candidate to the
Dick Howser Trophy as one of the three catcher semifinalists. ==Professional career==