The Broncos' defense has done a disservice to Peyton Manning.

Until last week, Denver's super-human unit masked the glaring deficiencies of their 39-year-old quarterback. But the last two weeks, without the defense coming to save the day, the future Hall of Famer simply has looked like an old quarterback.

And now the Broncos may be doing a disservice by keeping him in as their starter.

Questions About Benching Peyton Manning Creeping Up On Broncos

His diminished skills harken back to a time of another Hall of Famer whose game eroded quickly with age, according to Yahoo Sports.

"Since the start of Week 4, Manning has four touchdowns and 14 interceptions," Yahoo Sports reported. "You can argue he has been the NFL's worst regular starting quarterback this season. Willie Mays' fall in the outfield with the New York Mets was more graceful. ... The right move is to sit Manning for a while."

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Manning has been slowed by rib and foot injuries, and it was suggested before the game that the Broncos consider keeping him out, based on Manning's penchant to fade down the stretch in recent years.

Denver didn't bench him, and Manning had by far his worst outing as a professional.

He was 5-of-20 for 35 yards and four interceptions, equating to a 0.0 passing efficiency rating. His previous worst was a 31.3 rating in a 2003 playoff game against the Jets, Yahoo Sports added.

Yet, Broncos coach Gary Kubiak already has said he will not bench Manning.

"Peyton is our quarterback," Kubiak said after the game, according to USA Today. "If he's healthy and ready to go, he's our quarterback."

But even Manning questioned his own decision to try to play Sunday.

"I thought I felt good enough to play. That's what I thought. Maybe that was a false feeling," Manning said, according to the Broncos' Twitter feed. "It's really disappointing. I put our team in bad positions all day."

Denver already has proven that it can win games without stellar play from the quarterback -- or even without steady play from the quarterback.

Keeping Manning in the starting lineup appears to be inviting disaster. Kubiak is keeping Manning in the lineup because he is a Hall of Fame quarterback, but that is exactly why Kubiak should sit Manning.

How much more embarrassing can it get when Manning is benched on the day he breaks the all-time record for passing yards?

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