AJ McCarron, Nathan Peterman still leading the charge for Bills

Adrian Kraus/AP Photo

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 first-team offense since last Thursday. Allen, who has also not taken any reps with the second-team offense during training camp, has practiced exclusively with the third team the past four practices, which would suggest he will not play until the second half of the preseason opener.

While Thursday's game could determine how the Bills divide practice repetitions at quarterback next week before their second preseason game in Cleveland, it will likely take most or all of the preseason to sort out the team's Week 1 starter in Baltimore.

"The games are important," McDermott said Tuesday. "Up to this point, we haven’t had games to weigh. We had the spring in shorts and T-shirts, basically, and now we've had training camp, somewhat in pads, and now we'll have games to factor into that equation, that evaluation, and ultimately, that decision. Just like every position, we put a little more weight into games."

Through the first two weeks of training camp, here is an overview of one of the NFL's few starting quarterback competitions this summer:

AJ McCarron

Fifth year in NFL, first with Bills

What he's done well: McCarron has been the most risk-averse quarterback among the Bills' three, generally avoiding throws that could result in interceptions. He did throw an interception Tuesday by underthrowing a pass in what was a slower-paced 11-on-11 drill, and he was also picked off Monday when rookie receiver Robert Foster bobbled a pass. But generally, McCarron seems to be more inclined to check down to a running back or throw the ball away than try to force it into coverage downfield. He has generally been accurate on his shorter-range passes, but has not always been perfect.

Where he could improve: One of biggest issues through two weeks of training camp for McCarron is taking sacks. He seems to hold the ball longer than the other two quarterbacks, and even though the defensive line cannot touch McCarron, several plays have been whistled dead for apparent sacks. In an 11-on-11 drill in the red zone Monday, McCarron was sacked on three consecutive plays, although he threw the ball away at the whistle on the third play.

What he is saying: "I try to be the same guy every day. I try to bring -- I think if any of y'all actually watch me, I'm always having energy, I'm always pumping guys up. I feel like I always get the best out of the guys I'm playing with. That's my main job. Distribute the ball where it's supposed to go, but I always try to stay consistent, know how I play my game and be the best at it."

Nathan Peterman

Second year in NFL and with Bills

What he's done well: Peterman gained national attention last November for being intercepted five times in the first half of his first career start. That version of Peterman has not reared its head in training camp, or at all since the Bills began offseason practices in the spring. Peterman was picked off Sunday when safety Dean Marlowe undercut wide receiver Brandon Reilly's route, but Peterman responded later in practice to hit wide receiver Malachi Dupre for a first down on third-and-13 during a move-the-ball drill. The idea that Peterman is mentally rattled by his performance last season seems off-base.

Where he could improve: Peterman had a slow start to camp because of some inaccuracy issues that he seems to have cleaned up. He arguably outperformed McCarron in practice this week and flashed signs of being a precision passer when he went 6-for-6 in an 11-on-11 drill Monday, connecting on four passes that were more intermediate range than short-range gimmes. On deep passes, Peterman does not have Allen's arm talent and has underthrown some receivers in training camp.

What he is saying: "I think you got to carry good things with you, but also have a clean slate. To me, every rep is a new slate, trying to clear it out and then go perform my best. I don't think you can be tied to any past success or failure. I think I'm making steps here in fall camp, and I just got to keep doing that."

Josh Allen

Rookie first-round draft pick

What he's done well: McDermott on Friday complimented Allen for his "presence" and it does seem as though Allen has command of the huddle and is earning the respect of his teammates. When rookie receiver Austin Proehl failed to look back for one of Allen's deep passes Monday, causing an interception, Allen greeted Proehl back in the huddle with a tap on the helmet and presumably encouraging words. Allen has made some of the best throws of training camp and seems fearless in passing downfield, including when he found Dupre through traffic for about a 25-yard gain in Friday evening's practice.

Where he could improve: The consistency has not been there for Allen, which is not unexpected for a rookie. Some of his throws have been on target with excellent velocity, while others have been off target with perhaps too much velocity for the situation. Although Allen has been practicing with inexperienced receivers on the third team, it seems at times his receivers have trouble reacting to the speed of his throws and catching them. At other times he has overthrown receivers who simply are not fast enough to catch up to his deep ball.

What he is saying: "You kind of go through trial and tribulations just by failing in practice and understanding that it's OK to miss a throw or OK to miss a read. You look at Peyton Manning's first year in the league [in 1998]. It wasn't too pretty, but he bounced back from it and ended up being one, if not the greatest quarterback to ever play the game. He's a special guy and it takes a special mindset to have that, working on it every day through practice, making mistakes and understanding that if I make this mistake once, I can't make it again."