ORCHARD PARK, N.Y. — Before Sean McDermott could even be asked, the Bills head coach said there was no decision yet as to who will be the starting quarterback Sunday against the Chargers.    

"When you look at the quarterback play yesterday, this is a quarterback driven league and I thought at times there were some things that we're on target with and some times we weren't on time," McDermott said. "So we have to get better in every area of what we're doing. Not just the quarterback position, but every area."

McDermott wouldn't pin everything on Nathan Peterman, who finished with a zero QB rating in the team's worst lose since 2007 and the franchise's worst opening day loss ever. Rookie Josh Allen wasn't that much better in relief, but was able to move the offense and show a little of what he could do running the first team offense.

"We were going to throw the ball from that moment on when you're down that many points," said Bills offensive coordinator Brian Daboll. "So he was able to move around in the pocket, work on some plays concepts, see how he can move the ball downfield. Handled it like a pro. I'm sure there's some things that he'd like to have back just like all of us. But again, he's a young player that's still developing that I have a lot of trust in."

When it comes to choosing a quarterback, the Bills have to know already what they have in Peterman. The mystery lies with Allen, who the Bills traded up to draft seventh overall to be their franchise guy. So it's a matter of when, not if, and deciding if throwing the rookie in now is best for his future — even if it's clear he's currently the best for the job.

"There's a lot of things that will go into that decision," McDermott said. "Not to get into all the things I have to consider. It's not just as simple as some may think. There's a lot of hands in that jar and we have to look at the overall team in all three phases, Josh's development being one of them."

McDermott didn't rule out bringing in veteran QB, saying general manager Brandon Beane is always looking.