The six-foot-seven power forward was leading the team in scoring (16.9) and rebounding (9.3) last season before his season ended early when he tore a knee ligament against Louisiana-LaFayette in the eighth game of the season.
"Mack has been suspended indefinitely and will have the opportunity to rejoin the team subject to the progress he makes personally," Coach Cliff Ellis said. McGadney had a career-high in points (33) and rebounds (19) last season vs. Toledo.
Another senior, point guard Lincoln Glass, was suspended by Ellis earlier this month.
The Tigers begin full-scale practices Oct. 13 with a special "Midnight Madness" event scheduled for 12:01 a.m.