Coach Frank Haith did not provide further details while making the announcement Wednesday.
Dixon did not play in either of the 15th-ranked Tigers' exhibition games after an unspecified violation of team rules. He averaged 13.5 points as the team's sixth man last season and was expected to be in starting lineup this year.
Dixon was also suspended for violating team rules in December 2010.
Senior guard Keion Bell, who missed Missouri's second exhibition with a bout of pneumonia, will return Saturday.