Bills head coach Sean McDermott told reporters Monday that Allen will be under center for the Bills (3-7) when the team returns from its bye week for its game against the Jacksonville Jaguars on Nov. 25.
"If healthy, Josh Allen will start after our bye week," McDermott said. "He's been throwing and making progress but we'll take it one day at a time."
Allen, who was the seventh overall pick of the 2018 NFL Draft, has been sidelined with a right elbow injury that he sustained in a 20-13 loss at Houston on Oct. 14. The 22-year-old Allen has completed 75-of-139 passes for 832 yards with two touchdowns and five interceptions this season.
The 28-year-old Barkley has played in 12 NFL games during his career, completing 174-of-291 passes for 2,143 yards with 10 touchdowns and 18 interceptions.
McDermott said Monday that the move to Allen is about getting reps for the rookie as opposed to a reflection on Barkley.
Buffalo decided to give Barkley a shot after Nathan Peterman was ineffective in last week's 41-9 loss versus Chicago. Derek Anderson, who played in losses at Indianapolis on Oct. 21 and to New England on Oct. 29, is in the concussion protocol.