Bills head coach Sean McDermott said Allen is "progressing well," according to ESPN's Mike Rodak.
Allen has missed the Bills' past three games after suffering the elbow injury against the Houston Texans in Week 6.
Matt Barkley is another option for the Bills, although he's yet to be informed about his status for Sunday's game.
"I haven't been told anything (about starting). We're just preparing like all of us are preparing, like we can play," Barkley said, according to Rodak.