During his first two years at Michigan, in 2017 and 2018, he had 16 tackles and one interception. Thomas spent a month in the hospital before the 2019 season because he was diagnosed with colitis. Due to his ailment, he had to wait a year to heal, and when he returned, he became the starter for the first time. In that season, he started all 13 games and recorded 38 tackles and three interceptions. Thomas then chose to forego the 2020 season and join the NFL Draft in 2021.
Thomas was taken in the third round of the 2021 NFL Draft, according to the newest debate. He was once a four-star prospect who had to wait his turn. In the first two years of the game in Ann Arbor, he was forced to play behind La Vert Hill and David Long, but he finally got his shot when the San Francisco 49ers took him in the third round with the No. 102 overall choice.
