Allen cleared waivers and signed with the Bengals' practice squad Sunday, Tyler Dragon of The Cincinnati Enquirer reports.
The Broncos started Allen under center in three games last year, and the results were discouraging, as he completed just 46.4 percent of his passes for 515 yards, three touchdowns and two interceptions. He'll stick with the Bengals' practice squad as the franchise's No. 3 quarterback behind Joe Burrow and Ryan Finley.