ORCHARD PARK, N.Y. -- Buffalo Bills coach Sean McDermott on Wednesday named rookie Josh Allen as the starting quarterback for Sunday's game against the Los Angeles Chargers, repeating several times that he believed it was the "right move for our team" but declining to explain further.

"I don't feel a need, honestly, to elaborate," McDermott said about the decision to replace Week 1 starter Nathan Peterman following a 47-3 road loss to the Baltimore Ravens. "We talk a lot in-house about decisions and things and what we got to do, and the right move at the right time. Right now -- with all respect to your question -- this is the right move for us.

"With all due respect to the questions, I get it. There's some things that I can share, but there's some things that need to stay where they need to stay. I'm respecting where you guys are, and you need to respect where we are on this as well."

McDermott declined to say whether he intends to permanently switch to Allen as his starter. Allen, the No. 7 pick in April's draft, will become the second rookie quarterback from the class of 2018 to start. Sam Darnold, the No. 3 selection, made his starting debut Monday night for the New York Jets.

"[Allen] is prepared. He will be prepared. I don't think he's prepared yet -- it's a natural progression during a week -- but he'll be prepared," McDermott said. "At the end of the day, he's a young player. We keep that all in mind, manage expectations, and know that we embrace that growth mindset that there's going to be some challenges, some adversity, and you keep learning as you go and you embrace that."

Allen's athleticism and ability to make intermediate throws were plus-factors, and the staff believes those things will improve the running game, sources told ESPN's Chris Mortensen. Buffalo finished with 83 rushing yards, including 22 yards on seven carries by LeSean McCoy.

"Obviously I'm super excited and thankful for the chance to be the starter of this team," Allen said Wednesday. "This is something I've dreamed [about] for a long time. Now that it's here, come Sunday, I'm just trying to do my job, not trying to do much [and] trust in those around me. [I'm] ultimately trying to be the quarterback that this team needs, which is moving the ball, moving the chain on third down and putting points on the board."

While the Ravens dominated the Bills' offensive line, sources told Mortensen the evaluation of Sunday's game assigned three of the six sacks to the Bills' quarterbacks.

Allen replaced Peterman in the third quarter against the Ravens. With Peterman, who completed 5-of-18 passes for 24 yards, 2 interceptions and a 0.0 passer rating while being sacked three times, the offense failed to gain a first down until the first play of the second half.

McDermott said Wednesday that he made the decision to start Allen but consulted with general manager Brandon Beane and informed owners Terry and Kim Pegula of the move. McDermott, who named Peterman as his opening-day starter on Sept. 3, said he did not feel he misjudged his quarterback decision entering the season.

"Listen, I felt like -- just like this is the right move -- I felt like that was the right move," McDermott said. "And I'll take that to my grave."

Allen entered the game with the Bills trailing 40-0. He finished 6-of-15 for 74 yards and was sacked three times.

"I took a lot from it," Allen said. "I think if you saw the first drive that I was in, I was a little quick to get my eyes down. As the game went on, I felt a little more comfortable in trusting the guys in front of me and then the guys outside, just letting them go make some plays."

Added McDermott: "I thought his command of the offense was there. There were some things that he did well in getting us in and out of the huddle. Those are things you don't take for granted when a young player is out there. And then, after the snap, he executed fairly well at times and then there's times when we need to execute better. He moved well to put himself in position and generate some offense, I thought, within the pocket and then outside the pocket."

McDermott had previously described his development plan for Allen as "calculated," but said Wednesday the team needed to be prepared to start Allen at any point given his draft status.

"Experience is important," McDermott said. "He's going to get valuable experience from being ... behind the steering wheel. There's certainly valuable experience when you can stand and watch. But as we all know, there's no substitute for the experience when you're actually behind the wheel. There's a lot of value to that."

Peterman will serve as the Bills' backup quarterback with no other quarterback on the 53-man roster or practice squad.