Marshall started his college career as a cornerback for Georgia in 2011, but was kicked off the team and eventually landed at Auburn. In two seasons with Marshall as the team's starter, the Tigers went a combined 20-7, including a loss in the BCS title game to Florida State in 2014.
Marshall is playing in the Senior Bowl this week as a quarterback, but will return to defense in the NFL.
"It wasn't difficult because I played cornerback coming up," Marshall said of the decision. "It won't be a hard transition for me to make. It's something that I know if I put my mind to it I can do anything that I want."
In 2014, Marshall completed 60.8 percent of his passes for 2,532 yards, 20 touchdowns and seven touchdowns, while also rushing for 798 yards and 11 touchdowns. As a junior, he threw for 1,976 yards, 14 touchdowns and six interceptions, and he rushed for 1,068 yards and 12 touchdowns.
He is listed at 6-foot-1, 210 pounds and was a highly touted defensive back coming out of high school.
Auburn lost to Wisconsin in the Outback Bowl to finish the season 8-5.
- Paul Palladino