AJ McCarron, Nathan Peterman still leading the charge for Bills

PITTSFORD, N.Y. -- The Buffalo Bills will open their preseason Thursday night at New Era Field against the Carolina Panthers, but who will start at quarterback remains a mystery.

Coach Sean McDermott declined Tuesday to disclose how he would structure playing time for his quarterbacks, saying he wanted to share it with his team before the public.

However, it stands to reason that either AJ McCarron or Nathan Peterman -- or both -- will play in the first half Thursday. They were listed as co-starters on the team's unofficial depth chart released Monday and have alternated each day of training camp in leading the first-team offense.

Rookie first-round pick Josh Allen has not practiced with the…