Stewart started eight games last season after Taysom Hill was injured but has exhausted his NCAA eligibility.
"I was kind of in shock," Stewart said, according to the Associated Press. "I didn't think it was something that was possible. It was something I'd love to do. I love football. School is no fun just going to school. I felt like I was missing a big part of my life. I was happy to jump at the opportunity."
Hill is still recovering from a broken leg and backup McCoy Hill sprained his foot on the first day of practice and is expected to miss several weeks. The only other quarterback on the roster is Hunter Moore, who is running the scout team.
Without the stress of preparing to play season, Stewart said he is able to just go out and enjoy the game he loves.
"I don't necessarily feel any pressure, especially because what are the coaches going to do? Yell at me?" Stewart said. "They can't really get on me because I'm the one doing them a favor. But myself, I demand a lot out of myself."
BYU's spring game is on March 27.
- Josh Sanchez