MILWAUKEE (AP) -- Marquette University forward Trevor Mbakwe has quit the men's basketball team.

Head coach Buzz Williams says he was caught off guard and shocked by Mbakwe's decision. Williams says Mbakwe had a great summer in workouts and did well academically.

The 6'7" sophomore was expected to be a key contributor last year, but he suffered a knee injury and was out for most of the season.

Mbakwe told the coaching staff he decided not to return to Marquette for personal reasons. But, there was no specific information.

He remains in his hometown of St. Paul, Minnesota.