In 2024, Allen signed a one-year contract with the Steelers and played in one game. He was a third-string quarterback in Pittsburgh behind quarterbacks Justin Fields and Russell Wilson.
Allen also had stops in Houston, Washington and Carolina. With the Texans, he started in both games he played and had a 59 percent completion rate on 46-of-78 passes for 416 yards and two touchdowns. As a Commander, Allen he played in six games, making four starts. Across both seasons, 2020-21, he finished with a 67.9 completion percentage. Allen completed 72-of-102 passes for 730 yards and five touchdowns.
The Panthers signed Allen as an undrafted free agent in 2018 after finishing his last collegiate season at Houston. He spent his first two collegiate seasons at Texas A&M.
In Carolina, he played in 15 games and made 13 starts from 2018-19. He completed 323-520 passes for a 62.1 completion percentage. Allen threw for 3,588 yards and 19 touchdowns as a Panther with 3,322 passing yards and 19 passing touchdowns coming out of the 2019 season.