Mauk started the first four games of this season and has 26 starts at Mizzou. He was replaced in the starting lineup by true freshman Drew Lock, who has struggled as the Tigers have scored just 12 combined points in three losses to Florida, Georgia and Vanderbilt.
The Tigers are 21-5 when Mauk, a junior, has started. In his four starts this season, he completed 51.8 percent of his passes for 654 yards with six touchdowns and four interceptions.
Missouri (4-4, 1-4 SEC) has a bye this week and will host Mississippi State (6-2, 2-2) next Thursday on ESPN.
Mauk's reinstatement was earlier reported by the St. Louis Post-Dispatch.