Hampered by foot, rib, and shoulder injuries as well as the lingering feeling that this could be the end, Denver Broncos quarterback Peyton Manning experienced the worst game of his illustrious career as the AFC West leaders dropped their second straight game in Week 10.

In Sunday’s 29-13 letdown to division rival Kansas City, Manning surpassed Brett Favre as the all-time leader in career passing yards but would connect on just five of his 20 passes for 35 yards, four interceptions, and a 0.0 passer rating before head coach Gary Kubiak pulled him late in the third quarter in favor of backup Brock Osweiler.

ESPN’s Adam Schefter reported Monday morning that Manning aggravated a previously injured foot during the loss and put his status as starter for Week 11 at the Chicago Bears in jeopardy. 





After the game, Kubiak said he shouldn’t have played Manning in the first place.

It was not the first time the 39-year-old has played poorly this season. Against the Cleveland Browns on Oct. 18, Manning completed just 54.2 percent of his passes and was intercepted three times. He also was intercepted twice and threw for just 213 yards against the Minnesota Vikings on Oct. 4.

Though he showed similar signs of wear and tear towards the end of last season, Manning’s legendary career gave him the benefit of the doubt entering 2015. The 14-time Pro Bowler and seven-time first-team All-Pro went through a difficult final four games last season, tossing three touchdowns to six interceptions while fighting through a thigh injury that greatly limited his effectiveness in the postseason.

Those performances were seen as an outlier when compared to the rest of Manning’s career, but they’ve quickly become the norm. Manning has completed nine touchdown passes but also leads the NFL with 17 interceptions, a mark he’s reached only four other times. In 2010, 2002, 2001, 1998, Manning fired off 17 or more interceptions yet that was over the course of an entire season, and he’s now on pace for the worst interception-rate (5.3) and passer rating (67.6) of his career.

And overall the Broncos offense has suffered with Manning. Last season, Denver was third overall in total offense and was second in points scored with 30.1 per game. This season those numbers have dropped to No. 27 and a tied for No. 17, respectively.

Opposing defenses, including a Kansas City secondary that’s presently No. 15 in the league, have adjusted their game plans to neutralize Manning. The Chiefs took away any intermediate throws of 20 yards or less, and essentially dared Manning to use his limited arm strength downfield.

There was also a slight indication the Broncos, Kubiak, and even team president John Elway saw this precipitous decline coming. In June a report surfaced that Denver nearly traded Manning to the Houston Texans, though Elway and the Broncos later denied any link to a trade.

The Broncos are still in comfortable position in the division, holding a three-game lead over the Chiefs and Oakland Raiders. While their defense could keep them in the hunt with New England and Cincinnati for one of the AFC’s top two playoff seeds, it's unclear if Manning will be the quarterback to lead the team into the postseason.

Denver’s largely relied on its top-ranked defense to make up for Manning’s turnover woes throughout the season, but against Kansas City it missed leaders like cornerback Aqib Talib (suspension) and defensive end DeMarcus Ware (back), and receiver Emmanuel Sanders (ankle) and couldn’t withstand the Chiefs.

It was because of those injuries and Talib’s suspension that Manning reportedly forced himself to play in order to build Denver’s lead in the division and shake off Week 9’s at Indianapolis.

"I have a really hard time using my injuries as an excuse. I have a hard time saying that's why I played badly," Manning said to reporters after the game. "I was very honest with (athletic trainer Steve Antonopulos) Greek and coach Kubiak. I wanted to be out there for my team. But I certainly didn't play well, and I am disappointed about that."