Montague, the team's fourth-leading scorer with 9.7 points per game, has not played since scoring 16 points in Yale's 83-52 win over Cornell on Feb. 6. The school previously stated Montague was absent due to personal reasons.
The Yale Daily News reported Wednesday that Montague has withdrawn from school.
The Bulldogs are 3-1 without him this season.
"The Yale Athletic Department confirmed today that Jack Montague will not return to the men's basketball team," team spokesman Tim Bennett said. "There will be no further comment from the University."
With four games to go, Yale (9-1) is in first place in the Ivy League, which awards its automatic berth to the NCAA tournament to its regular-season champion.