OAKLAND -- As if the Raiders don't have enough to worry about.

Their season is a death spiral with five consecutive losses and seven in their past eight games. Jobs for players and coaches will be under review in the coming week.

But first, they get to play the Denver Broncos and Peyton Manning on Sunday at O.co Coliseum with both of their starting cornerbacks hurting or possibly even out of action.

With Mike Jenkins (hamstring) and Tracy Porter (hip flexor) questionable, the Raiders are preparing Chimdi Chekwa and Phillip Adams for potentially full-time duty against the most prolific passing offense in NFL history.

Manning already owns the NFL record for touchdown passes in a season with 51, and with 5,211 yards passing needs 266 to break that record of 5,476 yards set by New Orleans' Drew Brees in 2011.

The Broncos have scored 572 points, just 17 shy of the NFL record of 589 set by New England in 2007. With a 12-3 record, they go into the game knowing a win secures home-field advantage throughout the playoffs.

Even with Jenkins and Porter in the lineup, opponents have attacked the 4-11 Raiders successfully through the air.

Raiders coach Dennis Allen is approaching the game as if in blinders, invoking the "next man up theory" for his starting cornerbacks and paying no heed to speculation his job could be in jeopardy two years into a four-year contract.

Early this week, general manager Reggie McKenzie will meet with Allen and his staff, then report to owner Mark Davis to determine how to proceed into the 2014 season.

"Obviously, they're a really good team, fighting for the No. 1 seed in the playoffs, but we're not going to change our mindset," Allen said. "Our focus is going out and doing the things we have to do to try and have success."

Allen reinstalled Terrelle Pryor as the starting quarterback for the finale, looking to jump-start the running game as well as create some explosive plays.

"We just have to play a perfect game and move the ball," Pryor said. "Time of possession is going to be huge because we're going to play against the best quarterback in league history. We have to control the ball and take advantage."

Allen and McKenzie placed a premium on bringing in serious professionals, and pride will be a factor.

"Whether you're 1-0 or 4-11, every week is about remembering why you started playing football," linebacker Nick Roach said. "The big picture takes care of itself."

Although Wes Welker is out for the Broncos while recovering from a concussion, Manning still has Eric Decker (83 receptions, 1,261 yards, 10 touchdowns) and Demaryius Thomas (86 receptions, 1,317 yards, 12 touchdowns) to throw to, as well as tight end Julius Thomas (60 receptions, 752 yards, 12 touchdowns).

If Jenkins and Porter can't play or can't finish, it would be Chekwa, Adams and Chance Casey, a practice squad player for the first 12 games, coming in as the nickel back.

"I grew up in New Orleans, and I followed Peyton Manning when he was in high school there," Chekwa said. "To get an opportunity to play against him is exciting."

With 11 starters and a handful of others on one-year or expiring contracts, it's a final chance to make their cases for being around in 2014.

"This game will be important for them to go out and play well and compete against a really good team," Allen said. "Continuity is important. I certainly wouldn't want to go into next year with 10 new (defensive) starters like we had this year."

Only two Raiders coaches -- Marty Feldman in 1961 and Mike White in 1995 -- survived six losses to close the season and keep their jobs. White was under Al Davis.

While Allen would appear to have the support of McKenzie, there is no track record to help speculate how Mark Davis will react when the season is over.

"If you look at all that goes into it to have something turn around, progress has been made," Roach said. "In terms of wins, not as much as anyone would like to see, but to say we didn't accomplish anything would be false."

Follow Jerry McDonald on Twitter at twitter.com/Jerrymcd.

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