Allen will take most of the first-team reps during practice this week, Joe Buscaglia of WKBW.com reports.
Allen has already been named as the starter for Sunday's preseason game against the Bengals, essentially confirming that he's in the mix for the Week 1 starting job. Teams usually use the third week of the preseason to mimic their regular-season routine, and the Bills are doing just that by treating Allen as the starter all week. Nathan Peterman and AJ McCarron (shoulder) aren't out of the running just yet, but Allen can probably earn the job with strong showing in Sunday's game.