Bazelak's announcement on Twitter comes after he did not appear in the Lockheed Martin Armed Forces Bowl on Wednesday night due to what the school said was a leg injury. Redshirt freshman Brady Cook got the start in the Tigers' 24-22 loss to Army.
"This has been a tough decision that I have been thinking about for the last several weeks, but I wanted to be available for my team one last time in the bowl game," Bazelak posted on Twitter. "After much prayer and discussion with my family, I have decided to enter the transfer portal to continue my academic and athletic career."
Bazelak, who will have two years of eligibility remaining, appeared in 11 games this season. He completed 65.3% of his passes for 2,548 yards, 16 touchdowns and 11 interceptions.
A year ago, during coach Eli Drinkwitz's first season at Missouri, Bazelak threw seven touchdown passes and averaged 236.6 passing yards per game to share SEC freshman of the year honors with Auburn running back Tank Bigsby.
In two-plus seasons at Missouri, Bazelak, who is from Dayton, Ohio, threw for 5,058 yards with 25 total touchdowns (two rushing) and 17 interceptions.
"It has been a wild three seasons at the ZOU, and I have cherished every moment," he said.