ORCHARD PARK, N.Y. -- Of all of the teams to start 0-2 since 1990, only 8 percent have recovered to make the playoffs. The Buffalo Bills appear primed to join the 92-percent majority of that group -- and not simply because they are starting a rookie quarterback.

The Bills have much bigger problems than Josh Allen, who threw two interceptions in his starting debut, Sunday's 31-20 loss to the Los Angeles Chargers. He finished with an unexceptional 63.3 passer rating and abysmal 14.9 Total QBR for the game, the third-worst Total QBR of any quarterback this season but better than teammate Nathan Peterman's 0.9 in the opener.

Few were expecting Allen, making his first career start, to match Philip Rivers, making his 194th consecutive start, throw for throw in the Bills' home opener. But few also anticipated the Bills' defense would slip to the depths it did Sunday, allowing 28 first-half points and 284 first-half yards to the Chargers.

"He played a good quarterback today in Philip Rivers," Bills coach Sean McDermott said. "That guy, he's a wizard in terms of what he does before the ball is snapped, what he diagnoses. Because of that, he’ll be a Hall of Famer at some point. It was good for Josh to play across from him so he could watch him as well."

For the sake of coach McDermott's long-term future in Buffalo, he should hope Allen's best lessons aren't watching his coach's defense get thrashed on a weekly basis.

It would be one story if Allen, given his inexperience, was the weak link in a team that otherwise appeared headed in the right direction. But Allen and his predictable growing pains are simply one of many deficiencies for a club that has the experience and talent, especially on defense, to perform better than its start this season.

The Bills were embarrassed 47-3 by the Baltimore Ravens in their regular-season opener for their third loss by 30 points or more since McDermott became coach last year. Only 11 teams have suffered defeats by 30 points or more since the beginning of last season, and before the Cardinals' 34-point loss Sunday to the Rams, the Bills were the only team to which it has happened more than once.

The abhorrent start to the season prompted McDermott to remind fans in his news conferences, radio interviews and on the team-produced coach's show last week that the Bills were only in the second year of what is essentially a rebuilding project, even though McDermott resisted that label last year.

"[Fans] deserve better, first and foremost," he said last Monday. "We’re working hard to get it right. Like I said earlier, it’s not an easy process -- just being in the second year, it’s not an easy process. We’re trying to get this roster right and developing the right habits on and off the field. But I can promise you that no one is going to work harder to get it right than we are."

McDermott's plea for patience as it relates to Allen and first-year offensive coordinator Brian Daboll should not fall on deaf ears. However, greenness should hardly be an excuse for a defense that is captained by 13th-year veterans Lorenzo Alexander and Kyle Williams and also includes more than $30 million in average annual salaries that McDermott and general manager Brandon Beane committed to experienced free-agent pickups Star Lotulelei, Trent Murphy, Micah Hyde, Jordan Poyer and Vontae Davis since early 2017.

By halftime of Sunday's game, the Bills had been outscored 75-9 since the season began. That led to McDermott to take over playcalling duties from defensive coordinator Leslie Frazier for the second half. The results were good -- Buffalo held the Chargers to three second-half points -- but it would be impossible for McDermott to spin the decision into any sort of confidence in the defensive playcaller he hired.

McDermott stripping Frazier of his duties proved to be tame compared to what else happened in the Bills' locker room at halftime.

Davis, who was a healthy scratch in Week 1 despite spending the preseason as the Bills' presumptive starter at cornerback, retired at halftime in one of the most unique bizarre NFL stories in recent memory.

Nobody expects McDermott or Beane to be perfect in their decision-making, but the move to sign Davis this offseason to a deal is one of many mounting calls -- large and small -- that could begin to erode fan confidence in the team's leadership. Buffalo guaranteed Davis $3.5 million and will likely recover most of that, but are now left scrambling to find cornerback help.

On Saturday, the Bills made the surprising move to release veteran wide receiver Jeremy Kerley in order to carry a fourth defensive tackle for Sunday's game. That not only took away Allen's slot receiver for his first start, but also stripped the team of its primary punt returner. Backup punt returner Marcus Murphy muffed two third-quarter punt returns Sunday, including a dropped ball that Bills special-teams captain Taiwan Jones had to recover in the end zone for a touchback, a play that was painful in more ways than one.

While attempting to avoid a tackle, Jones had his helmet ripped off and then got his bare head rocked by the shoulder pad of Chargers linebacker Uchenna Nwosu. Blood gushed from Jones' forehead and he was taken directly to the locker room.

That was not even the lowest moment for the Bills' special-teams unit Sunday. On a punt in the fourth quarter, several Bills defenders surrounded the ball as it wobbled toward the end zone, only to allow the ball past the goal line for a touchback before it was touched down.

Such is the state of the 2018 Bills, a team that entered the season with the longest odds by some Las Vegas sports books to make the playoffs and now must play four of its next five games on the road. That potentially season-spiraling journey starts this Sunday in Minnesota, where the Bills are 16.5-point underdogs to the Vikings.