AFC Divisional Round Preview: Peyton Manning's Swan Song

Even before the weekend hits, we've got drama in the NFL. Plenty of big-name players have injury concerns, and that's making it difficult to see how some of these games will play out.

Let's dig into some of the numbers and storylines for the AFC games this week, though, and see if we can make some sense of what's going to play out.

New England Patriots vs. Kansas City Chiefs

No surprise here -- for the sixth straight year, the Patriots are making their playoff debut in the divisional round after securing a first-round bye. They'll be taking on a Chiefs team that finished the regular season 11-5, just one game back from the Denver Broncos in the AFC West.

The Patriots are consistently one of the top teams in the NFL, and this year is no different. Offensively, they ranked third in the league according to our Net Expected Points (NEP) metric when adjusted for strength of schedule. The defense didn't trail far behind, coming in at 12th overall.

At the risk of boring you with more of exactly what you expected, Tom Brady once again proved himself to be one of the best quarterbacks in the league, and among the 37 quarterbacks to record at least 200 drop backs on the year, his passing NEP ranked fourth on a per-drop-back basis. On average, every single time Brady dropped back to pass, he contributed just a shade over 0.25 points to the Patriots' expected total. His raw numbers were great, too, throwing for 4,770 yards and a league-leading 36 touchdowns, both his best marks since 2011, while limiting his interceptions to 7, the second-lowest mark of his career.

While no team makes it this far into the year without injury troubles, Brady managed those gaudy numbers with three of his best offensive weapons -- Dion Lewis, Julian Edelman, and Rob Gronkowski -- missing at least some time due to injuries.

Lewis tore his ACL and is done for the season, but barring any late setbacks, Gronkowski and Edelman will both be returning to the field this weekend.

Gronkowski and Edelman are the Patriots' two most efficient pass-catchers according to our metrics, and Brady's numbers vary greatly with and without them. Over the last two seasons, when Edelman plays, Brady has thrown for 0.9 more touchdowns and 0.8 fewer interceptions per game, and his yards per attempt jump by 1.29. Without Edelman this season, Brady had a below-average Passing NEP per drop back rate, while his rate was the league's best with Edelman.

That's a drastic difference, and if they can hit the ground running, the Patriots' offense is as good as any in the league.

When Brady is on top of his game like he has been this season, aiming to simply slow him down is a much more realistic goal than trying to stop him. But the Chiefs' defense may well be up to the task. They rank fourth in schedule-adjusted Defensive NEP, and have been strong against both the run, ranking eighth, as well as the pass, ranking fourth.

One of the few consistent ways that opposing defenses have been able to make Brady struggle has been by getting pressure on him, and the Chiefs are well positioned to do that. The duo of Justin Houston and Tamba Hali haven't been as prolific this year as in years past, but the Chiefs defense still managed to finish the season ranked seventh with 0.07 sacks per opponents' drop back.

Behind that pass rush is Defensive Rookie of the Year candidate Marcus Peters and first team All-Pro Eric Berry, who will play the biggest roles in Kansas City's efforts to stay with Gronkowski and Edelman.

The Patriots have really struggled to run the ball since Lewis went down, and while James White has stepped up admirably in the passing game, he simply can't fill Lewis' role, as I wrote about earlier this week. When the Patriots are on offense, this game is going to be won and lost through the air.

There's considerably less intrigue when the Chiefs are on the field. Our metrics have Kansas City's offense ranked 14th, and the Patriots' defense ranked 12th.

The Chiefs are the seventh most run-heavy team in the league, with a 1.18 pass-to-run ratio this season, and that's also where they've been the most effective. While their passing offense only ranks 19th, their rushing offense finished the season ranked second, despite losing top back Jamaal Charles early in the year.

The Patriots defense ranked 12th against the run this year, and having Dont'a Hightower getting closer to 100 percent healthy will be big for their ability to stop the Chiefs' rushing attack.

A big question mark surrounding the Chiefs' offense is how they will play if they fall behind early and can't lean on the run game. Their passing offense ranked 19th this year, and Alex Smith's 0.08 Passing NEP per drop back also ranked 19th. Things become especially difficult with Jeremy Maclin's injury. Even if Maclin can play, he'll be limited, which also limits a huge part of the Kansas City aerial attack. Maclin has accounted for 35 percent of the Chiefs' targets through their last six games, and his 0.70 Reception NEP per target is the best mark among Chiefs' players with at least 25 targets.

The Patriots defense ranked 12th against the pass this season, and had one of the best pass rushes in the league, recording the second most sacks per opponents' drop back. If the Chiefs fall behind early, it's going to be a massively uphill battle -- the Patriots defend the pass fairly well, and Alex Smith is not the guy you want your playoff hopes resting on the shoulders of.

numberFire Live has the Patriots' odds of winning at 62% right now, projecting this as the second closest game of the weekend.

Denver Broncos vs. Pittsburgh Steelers

The last time the Steelers and Broncos faced off in a playoff game, there was no shortage of excitement. The game came down to Tim Tebow connecting on a game-winning 80-yard touchdown pass to Demaryius Thomas in overtime. This one might not be as close -- the numberFire Live numbers have the Broncos' odds of winning at 65%.

The Steelers' offense ranks fourth in our Net Expected Points metric this year, ranking as the ninth best passing and fourth best rushing offense. They played the Broncos earlier in the year, and were the only team to find major success against them. Ben Roethlisberger became the first quarterback to throw for 300 yards against the Broncos, and the Steelers were the first team to score 30 points against them. This time around, though, that Steelers' offense may not even be recognizable as the same unit.

Roethlisberger suffered a shoulder injury against the Bengals last week, and has been limited in practice this week. It looks like his status will be a game-time call. If he can't go, Landry Jones will be at the helm for Pittsburgh. Also injured last week was star wide receiver Antonio Brown, who was just ruled out for the game on Sunday. PIttsburgh will also likely be without DeAngelo Williams, who became their starting running back when Le'Veon Bell went down for the season, as he's still recovering from a foot injury.

The step down from Roethlisberger to Jones is a huge one. Big Ben ranked fifth among quarterbacks with a 0.25 Passing NEP per drop back in 2015. Among the 51 quarterbacks to record at least 50 dropbacks on the year, Jones' 0.04 Passing NEP per drop back ranked only 34th. What this effectively means is that, on average, every five dropbacks that Jones takes are worth a full point less than five drop backs from Roethlisberger. Not ideal for a team that averaged just over 36 dropbacks per game in the regular season.

Taking away Pittsburgh's best weapons will make things even harder on Jones, if he were to get the nod. Antonio Brown contributed a massive 147.21 Reception NEP this season, more than Markus Wheaton (63.19) and Martavis Bryant (60.27) combined. Brown was the only receiver to catch more than 10 passes against Denver this season, as well as the only receiver to record at least 125 yards or score 2 touchdowns against them. Without Brown, this could be a long day for the Steelers offense.

Denver has a phenomenal pass rush, leading the league with 0.08 sacks per opponents' drop back. And they have one of the best secondaries in football behind it, led by Chris Harris, Aqib Talib and T.J. Ward.

Pittsburgh's running game may not offer a ton of help for the offense this week, either. Not every offense can thrive even after losing a player of Le'Veon Bell's caliber, and it'll be even harder for Pittsburgh with DeAngelo Williams out. Among the 72 backs to record at least 50 carries on the season, Williams' 0.07 Rushing NEP per carry ranked eighth. He allowed the Steelers to use a balanced attack on offense, and really thrived in his workhorse role.

His potential replacements are Jordan Todman and Fitzgerald Toussaint. Neither are particularly exciting backs, though Todman managed a 0.53 Rushing NEP last week on 11 carries, while Toussaint posted a -2.03 Rushing NEP on 17 carries. Neither of these guys are more than likely going to thrive if asked to shoulder a major workload against Von Miller, Derek Wolfe, and the Broncos' fifth ranked run defense.

Of course, it's impossible to talk about this game without bringing up one of the biggest stories surrounding it: Peyton Manning's swan song.

Manning, for how incredible he's been throughout his career, and for how highly he stands in the all-time quarterback picture, has been terrible this year. His efficiency ranks 32nd among the 37 quarterbacks with at least 200 drop backs, posting a -0.02 Passing NEP per drop back. Even his backup, Brock Osweiler, managed a better season, ranking 22nd among that group with a 0.08 Passing NEP per drop back. It's really not a major stretch to suggest that Osweiler would give the Broncos a better chance at winning this week, but he hasn't been practicing all week, and it may be a moot point when Trevor Siemian backs up Manning on Sunday.

Another consequence of the Broncos' anemic passing offense is that they also struggled to run the ball. They ranked 27th in schedule-adjusted Rushing NEP, two spots behind their Passing NEP ranking. While both C.J. Anderson and Ronnie Hillman eclipsed 150 carries on the season, neither managed to crack the top half in rushing efficiency among the 72 backs with 50-plus carries on the season.

The Broncos will be up against a Steelers defense that was quietly good this year. Our Net Expected Points metrics had them ranked fourth against the run, ninth against the pass, and ninth overall. They also forced turnovers at an excellent rate, ranking fourth in takeaways per opponents' snap.

With both teams fully healthy, we'd be treated to a matchup between the Steelers' elite offense and the Broncos' elite defense. And it would be hard to pick a side. As things stand, though, the Broncos look like clear favorites in this one, and according to our numbers, they're the second biggest favorites of the weekend.