Bragg, a senior from Texas, posted on Twitter that he has "long-term" and "intense" symptoms stemming from a concussion he sustained during Stanford's training camp. He also cited mental health factors as contributing to the decision. Bragg did not play in Stanford's first two games.
The 6-foot-4, 315-pound Bragg started nine games at right guard and right tackle last season, and started all six games in 2020 at right guard. He earned honorable mention All-Pac-12 honors from the league's coaches last year.
"I'm confident that stepping away is the best decision for me," Bragg wrote. "The past four years at Stanford have been everything that I could've hoped for, and I created countless lifelong bonds while living out my dream with the best teammates and support staff in the world."
ESPN rated Bragg as the No. 152 overall recruit in the 2019 class. Bragg wrote that he's on track to graduate with his degree in mathematical and computational science.