ENGLEWOOD, Colo. -- A missed practice by Peyton Manning is a rarity, so unusual during his long, durable career that when it happened Wednesday, as the Denver Broncos were preparing for their biggest game of the season so far, it sent a brief shudder through Denver, even though his absence to rest a high ankle sprain was anticipated.
The stability of Manning's ankles is this season's concern, temporarily replacing the fixation on his arm strength. It is a mark of just how much the Broncos' fate hinges on Manning remaining in one piece that questions about his health have completely overshadowed the fact that head coach John Fox, who is recuperating from heart valve replacement surgery, might be off the sideline for the rest of the regular season.
While Fox's recovery is progressing well, there is no getting around the fact that he will have nothing to rush back to if Manning's injuries begin to significantly impair his performance. Nobody could recall Manning ever missing a practice while he was with the Indianapolis Colts, at least until his neck surgery short-circuited his 2011 season.
Still, if a reminder of Manning's physical toughness is needed as the Broncos (8-1) head into a critical three-game stretch that begins with Sunday's showdown with the Kansas City Chiefs (9-0), there is this: Before sitting out for the entire 2011 campaign, Manning had missed just one snap to injury in his professional career, when he suffered a broken jaw in 2001 -- and only briefly left the game. In 2008, he missed most of training camp and the entire preseason after having surgery that July to remove an infected bursa sac in his knee -- and went on to win the third of his four MVP awards.
When a reporter asked if he still anticipated playing Sunday, Manning gave him a sideways glance suggesting disbelief that this could even be in doubt.
"I am, yes."
And could he have played if the game had been on Wednesday?
"Yeah," he said. "They're not going to Wednesday games yet, are they?"
This is the new reality for Manning, who returned to the practice field Thursday. He will skip the occasional workout if he has to, a concession to his post-neck-surgery body and his age, even though he frets about missing the chance to further hone his timing with receivers. One of those receivers, Demaryius Thomas, laughed at the idea that Manning has anything to worry about.
"Nah, I'm fine; he's been doing this for a long time," Thomas said. "If he loses it from missing one practice -- it's not going to happen. I just want my quarterback to be out there on Sunday."
For good reason. Sunday's matchup is compelling not just because it will add another chapter to a traditionally fierce division rivalry, or because it (along with a rematch in Week 13) likely will determine playoff seeding (ending up with a wild-card spot would be a stunning outcome for Denver). The contest will provide the ultimate litmus test for how football is played today: the league's top scoring offense (the Broncos, averaging 41.2 points per game) versus the league's top scoring defense (the Chiefs, allowing 12.3 points per game). Kansas City also leads the league in sacks, although the team's standing in that area is questioned because five of the quarterbacks it's faced have been backups at some point in the season -- a number that grows to six when Michael Vick, who seems to have lost his grip on the starting job in Philadelphia, is included.
If the Chiefs are feeling disrespected, they might be heartened by Manning's mixed track record against top-ranked scoring defenses. Six times in his career, Manning has faced the top scoring defense in the second half of the season or in the playoffs. In those games, his teams went 3-3, with Manning giving up eight interceptions while throwing just six touchdowns and averaging 201.8 passing yards per contest -- well below his average of 361 yards this season.
Manning and the Broncos face a unique challenge in Kansas City's defense, which has been able to create pressure even without blitzing. That will be a concern, given the Broncos' offensive line struggles -- though it's worth noting that the Chiefs didn't touch Jeff Tuel in Kansas City's most recent game, a win over Buffalo. Additionally, K.C. specifically acquired bigger cornerbacks to counteract Denver's looming receiving duo of Thomas and Eric Decker. The Chiefs likely will try to press the receivers to throw their timing off, which would force Manning to hold the ball a bit longer, making him and his tender ankles more susceptible to the pass rush.
Holding Manning at bay -- and limiting the Broncos to field goals instead of touchdowns -- would seem to be the Chiefs' surest path to victory. Kansas City's offense has been so conservative (preferring shorter passes and lengthy, deliberate marches down the field) and recently so nonproductive (the Chiefs have scored just 16 offensive touchdowns on the season, while quarterback Alex Smith has thrown two touchdown passes over the past five games), that the unit likely would struggle to catch up if the Broncos were to take a quick lead.
It's hard to imagine Kansas City keeping pace with Denver in a shootout, as the Dallas Cowboys (who lost) and Indianapolis Colts (who won) were both able to do in the Broncos' toughest games this year. Manning's average gain per pass is 8.81 yards, second in the league. Smith, meanwhile, picks up just 6.09 yards per pass, which ranks 29th.
Ironically, Jack Del Rio, the Broncos' interim head coach and defensive coordinator, was on the Baltimore Ravens staff that won a Super Bowl in the 2000 season by relying on the top scoring defense, which allowed just 10.3 points per game. Baltimore's offense that year, when the Ravens averaged just 20.8 points per game, is remembered for a five-game stretch in which it did not score a touchdown. Of course, the 2013 Chiefs, who score 23.9 points per game, haven't approached the same level of futility as those Ravens.
Still, this game -- along with the sequel in two weeks -- feels a little like a referendum on the notion that it is still possible to contend without a high-powered offense. Del Rio said he did not yet see similarities between these Chiefs and those 2000 Ravens, because K.C. has not sustained its defensive success over a season. Ultimately, though, the Broncos and their banged-up quarterback might be the only ones who can put an end to those comparisons.
And here are 10 more things to ponder heading into Week 11:
1) How does Luke Kuechly handle Rob Gronkowski? Carolina is the only team in the league ranked in the top five in total defense, scoring defense, rushing defense and passing defense, and it has allowed 15 points or fewer in seven of its nine games. Kuechly, a Defensive Player of the Year candidate, is the Panthers' anchor, collecting 75 tackles, one sack, three interceptions and five passes defensed this season. Against the Patriots, he likely will draw time on Gronkowski, whose return has opened up New England's offense. Since the tight end's season debut three games ago, the Pats are posting 36.3 points per game -- 15.5 more than they averaged when he was out.
2) Will the arrest of receiver Dwayne Bowe affect the Chiefs against the Broncos? Bowe will start, but his impact on the Chiefs' low-scoring offense has been minimal so far this season: He has 33 receptions for 369 yards and two touchdowns. Donnie Avery is the Chiefs' leading receiver with 396 yards -- that's the second fewest yards for any team's leading pass catcher. (Jeremy Kerley paces the New York Jets with a paltry total of 347 yards.)
3) What will a revived Giants defense do against fill-in Packers quarterback Scott Tolzien? Tolzien, who came in last week after Seneca Wallace was hurt early in the game, showed promise, completing 24 of 39 pass for 280 yards, a touchdown and two interceptions. The Giants' defense, meanwhile, has allowed just one offensive touchdown in the past 14 quarters, or 18 fewer than it had allowed in the first 22 quarters. New York's passing defense has not allowed a touchdown during the team's three-game winning streak. Tolzien figures to be under pressure -- the Giants have eight sacks in the past two games.
4) Can the 49ers get their offense back on track against a Saints' defense that just stifled Tony Romo and the Cowboys? San Francisco's offense gained just 151 yards against the Panthers last week. Colin Kaepernick, meanwhile, is averaging just 186.1 passing yards per game, 32nd in the league among quarterbacks with enough passes to qualify. Kaepernick, who also has the NFL's worst fourth-quarter passer rating, might struggle to go deep against the Saints if the Niners fall behind. New Orleans has held opposing quarterbacks to a league-low passer rating of 37.8 on throws at least 21 yards downfield. Kaepernick's passer rating on such throws is 66.8.
5) Will the Redskins slow down the Eagles this time? Philly ran 53 plays, accumulating 21 first downs and 322 yards of total offense, in the first half of the season opener against Washington, coasting to a 33-27 victory. At that time, the Redskins' offense couldn't sustain drives, but in the past two weeks, Washington has run for 400 yards. Expect both squads to emphasize the ground game, as they are the only teams in the NFL to average more than 5 yards per run this season.
6) Can Josh McCown really make Bears fans forget Jay Cutler this quickly? With Cutler (high ankle sprain) out on Sunday, it will fall to McCown to keep the Bears in the chase for a playoff berth. A big part of Chicago's offensive success behind either quarterback is that the team has allowed just 14 sacks total, the third fewest in the league.
7) Can the Dolphins figure out how to run the ball and stop their freefall? In their first game missing both Richie Incognito and Jonathan Martin on the O-line, the Dolphins ran for just 2 -- TWO -- yards against Tampa Bay. The loss was their fifth in six games. Another defeat could end any playoff hopes. On Sunday, they'll face a Chargers' defense that, while it ranks 20th against the run, just became the first team to hold the Broncos under 30 points and 400 total yards.
8) Can the Jets win two games in a row? They haven't so far this season. Against the Bills, they are likely to rely on a nascent running game -- which has gained at least 175 yards in two of the team's past three games, both wins (over the Patriots and Saints) -- to offset quarterback Geno Smith's mini-slump. The rookie, who has thrown one touchdown and five interceptions in the past four games, has followed wins with poor performances all year. His passer rating in games following wins is 51.7, while it is 92.8 in games following losses.
9) Will Bengals quarterback Andy Dalton continue to go off the rails against the Browns? The Bengals have lost two in a row -- in overtime -- and Dalton has been terrible, giving up six interceptions in those games after getting picked off just seven times in the season's first half. Cleveland's defense held Cincinnati to 266 total yards in their first meeting this season, marking the unit's best performance of the year. The Browns' defense ranks fifth overall, sixth against the run and 10th against the pass.
10) Will the changing of the guard hold up? Entering Week 11, seven of the eight division leaders did not win their respective divisions last year. The only repeaters were the New England Patriots in the AFC East. Of course, there's still much to be decided, as 23 teams are either in or within 1 1/2 games of a playoff spot.
Follow Judy Battista on Twitter @judybattista.