Both players will miss the 15th-ranked Tigers' first exhibition game Monday against Northwest Missouri State. Coach Frank Haith announced the suspensions Friday but declined to offer any details.
Dixon is a senior who averaged 13.5 points per game as the team's sixth man last season and is expected be in the starting lineup when the season begins Nov. 10.
Dixon was also suspended for violating team rules in December 2010. Bull is a freshman from Worcester, Mass.