"I would like to thank Coach Majerus, the coaching staff and my teammates for the opportunity to be a part of the Billiken basketball program," Thompson said in a press release.
Thompson played in 30 games during the 2008-09 season, averaging 11.4 minutes per game and starting seven games. He averaged 2 points and 2.5 rebounds per game. He scored a high of eight points against Samford on Dec. 13 and grabbed eight rebounds against Savannah State on Dec. 6.
The post player, who was listed at 6-feet-10 and 260 pounds as a freshman, shot 40 percent (22 of 55) from the field and 72 percent (13 of 18) from the free-throw line.
"Brett Thompson is a quality young man," Majerus said in a statement. "We wish him every success in the future and thank him for the contributions he made to the program last season."
Thompson becomes the second player from last year's recruiting class, rated by Scout.com as the second-best in the Atlantic 10 Conference, to decide to transfer. Guard Ruben Cotto opted to leave after playing just seven games.
The Illinois native's decision to transfer figures to open up more playing time for returning forwards Willie Reed and Brian Conklin as well as incoming forwards Cody Ellis, Jonathan Smith and Cory Remekun.