Gilbert would join his younger brother Marcus, a freshman, at Fairfield, which is the reason he opted to leave Pitt, according to coach Jamie Dixon in the Pittsburgh Tribune-Review.
"Malcolm has asked for his release and has informed me that he wants to play with his brother," Dixon said in a statement. "He`s a great kid, hard worker and good player. We thank Malcolm for his contribution to our program over the last year and a half and wish him much success in the future."
Fairfield coach Sydney Johnson was not available for comment.
The 6-foot-11 Gilbert planned to redshirt this season at Pitt after playing limited minutes in 19 games last season.
Marcus Gilbert is averaging 6.0 points and 2.7 rebounds for the 8-5 Stags, who play at Old Dominion (2-10) on Saturday night.
Fairfield, which added five freshmen this season, already has Seton Hall transfer Sean Grennan eligible for next year along with three incoming freshmen: G Lincoln Davis, G Doug Chappell and F Steve Smith.