Bills to start Josh Allen at QB vs. Chargers

Josh Allen will become the second rookie quarterback from the class of 2018 to start when the Buffalo Bills play the Los Angeles Chargers on Sunday, league and team sources told ESPN's Chris Mortensen on Wednesday.

Bills coach Sean McDermott is expected to make it official later Wednesday.

The decision by McDermott and his staff came after a full evaluation of Sunday's 47-3 road loss to the Baltimore Ravens, sources said. Allen, who was drafted with the seventh overall pick, had replaced starting quarterback  Nathan Peterman in the third quarter and finished 6-of-15 for 74 yards and was sacked three times.

Allen's athleticism and ability to make intermediate throws were plus-factors, and the staff believes they will improve the run game, sources told ESPN.

"I thought he made some pretty decisive throws in there, into some tight windows. He used his feet at times, as well," McDermott said after Sunday's game. "I thought he had pretty good command of the huddle and the offense at the line of scrimmage. Other than that, we'll go back and look at the film and evaluate it."

While the offensive line was dominated by the Ravens, sources said the evaluation of Sunday's game also assigned three sacks to Peterman, who moves into the backup role behind Allen.

Against the Ravens, Peterman completed 5-of-18 passes for 24 yards, 2 interceptions and a 0.0 passer rating. Peterman and the offense failed to gain a first down until the first play of the second half.

It was the first time Buffalo failed to gain a first down in the first half of any game since at least 2001, while Buffalo's 33 total offensive yards in the first half were the team's fewest in any game since they gained 11 against the Miami Dolphins in a December 2003 game.