Allen, 24, initially signed with the Bears in May 2018. He has not played in a regular-season game.
Beavers, 25, played in two games as a rookie with the Vikings in 2016. Minnesota made him a fourth-round choice that year.
He has spent time on the practice squads of the Patriots and the Seahawks before signing with the Bears’ practice squad last Nov. 5.
Grayson, 25, has spent time on the practice squads of the Seahawks, Colts and Texans. He joined the Bears’ practice squad last Nov. 27.