AP Photo/Morry GashAaron Rodgers had some nifty scrambles against the Giants, but he did his best work with his arm. Rodgers threw for 404 yards and four TDs, leading Green Bay to a 45-17 victory. Week 16 leaders

The AFC playoffs are almost set. The NFC playoff picture is about as unclear as the snowy skies in Philadelphia that postponed the Eagles-Vikings game until Tuesday night.

The Kansas City Chiefs and Baltimore Ravens clinched playoff spots with victories Sunday, while the Indianapolis Colts all but locked up the AFC South with a 31-26 victory over the Oakland Raiders. The Colts only need to beat the Tennessee Titans next Sunday at home to win the division. The New England Patriots locked up home-field advantage.

"It's a huge accomplishment," Chiefs quarterback Matt Cassel said of his team's rise from 4-12 to the playoffs. "Adversity was difficult to handle at times last year. To be here with 10 wins is remarkable to say the very least."

In the AFC, next Sunday is all about playoff seeding. The New York Jets, who probably are going to get the No. 6 seed, are thinking about resting quarterback Mark Sanchez. They would end up playing the Chiefs in the playoffs if Kansas City wins and gets the No. 3 seed.

The Ravens seem destined for a wild-card game against the Colts, if the Colts win next Sunday.

The only things accomplished in the NFC were the Green Bay Packers getting back into the race with a 45-17 win over the New York Giants and the Philadelphia Eagles clinching the NFC East title by virtue of that game. The Packers will get the No. 6 seed if they beat the Bears next week. The New Orleans Saints can lock up a playoff spot Monday night with a win over the Atlanta Falcons.

Here are five things I learned in Week 16.

1. Uncovering defenses: "It was a defensive struggle," Chicago Bears linebacker Lance Briggs said after a 38-34 victory over the Jets. "The defenses struggled." Both Rex Ryan of the Jets and Lovie Smith of the Bears are defensive head coaches, but it was their offensive strategies that exposed problems for the opponent's defense. For the second consecutive Bears home game, an AFC East team -- the Jets on Sunday and the Patriots two weeks ago -- showed ways to beat the Bears' Cover 2 defense. The Jets had Sanchez work more three-step drops and quick throws -- particularly slants to Braylon Edwards and Santonio Holmes -- that kept drives moving.

Sanchez showed no ill effects from the slight cartilage tear in his right shoulder and zipped strong passes. He completed 24 of 37 passes for 269 yards.

"Every defense has weaknesses," Bears defensive end Julius Peppers confessed after the game. The Bears were victimized for 124 yards rushing; it could be worse in the playoffs against teams that have big, powerful running backs.

On the flip side, Bears coaches presented an intriguing game plan that baffled the Jets' blitzing defense. Offensive coordinator Mike Martz mixed in more two- and three-tight end sets that neutralized the Jets' pass rush. Occasionally, Martz would place a tight end as an outside receiver to cause matchup problems for the Jets' man defense. It caused receivers to occasionally be covered by safeties and tight ends to be covered by cornerbacks. Those strategies opened up some big plays for Jay Cutler, who threw touchdown passes of 40, 25 and 26 yards.

Cutler was pressured, but he was sacked only twice and hit four other times, small numbers for a Bears team that has offensive line problems. The Bears, meanwhile, who rarely rush more than four defenders, didn't sack Sanchez and hit him only once. The film from this game could be used to make both teams one-and-done during the playoffs.

2. Error of Singletary's ways: Other than how Eric Mangini mismanaged Brady Quinn and Derek Anderson off the Cleveland Browns' roster, I don't think I've ever seen a worse job of managing quarterbacks than that done by the 49ers' Mike Singletary. That mismanagement was among the factors that led to his firing on Sunday night. The move to go back to Troy Smith as the starter for a win-or-get-fired game against the St. Louis Rams was foolhardy. Smith, brought in as a third-stringer behind Alex Smith and David Carr on Sept. 6, was moved ahead of Carr and got five starts when Alex Smith was banged up. A good leader, Troy Smith provided some spark, but opposing defenses figured him out, particularly when Frank Gore was lost for the season. Troy Smith works best as a play-action quarterback, and minus Gore he wasn't the same quarterback.

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Dilip Vishwanat/Getty ImagesTroy Smith was put in the tough spot on Sunday, and the results weren't pretty.

You knew Troy Smith was doomed on Friday, when Anthony Dixon showed up on the injury report as questionable with an ankle injury. Dixon is the big back, while Brian Westbrook is the lighter, more elusive back who fits Alex Smith's passing offense better than Troy Smith's run-based attack. As a result, Smith was 7-of-19 for 153 yards and was benched with 9:53 left in the fourth quarter.

Except for one start, Troy Smith never established a passing relationship with tight end Vernon Davis. Alex Smith came off the bench on Sunday, but didn't have enough time to pull off the comeback.

Owner Jed York said after the 25-17 loss that he will start a general manager search this week. Defensive line coach Jim Tomsula will coach the team's game against Arizona in Week 17, and the coaching search will begin after that. The contracts for both quarterbacks expire at the end of the season, and one thing's for sure: The 49ers can't go through another season of quarterback turmoil and bad management like they have this season.

3. Chargers bitten by bad habit: It's pretty clear why the San Diego Chargers lost the AFC West title to the Chiefs -- they couldn't overcome yet another slow start. Against what was supposed to be an easy schedule, the Chargers started 2-5. They've shown that habit the past couple of years, when they were 2-3 in 2009 and 2-6 in 2008 but were chasing only a Denver Broncos franchise that faded in those seasons, giving the Chargers the chance to make the playoffs. The difference this year is the Chiefs didn't fade. In what was the equivalent of a playoff game, it was fitting the Chargers got off to a slow start in a 34-20 loss to the Cincinnati Bengals.

The Chargers did even worse than waste Philip Rivers' best season (4,396 yards and 30 touchdowns): They left their roster in a vulnerable position. Wide receivers Vincent Jackson and Malcom Floyd, halfback Darren Sproles, safety Eric Weddle, linebacker Stephen Cooper and defensive end Jacques Cesaire are among 21 potential unrestricted free agents next year. And talented defensive coordinator Ron Rivera could be lost to a head-coaching job.

The window clearly might be closing for the Chargers, unless they can figure out a way to start fast. That might be tough if they don't have a good offseason.

4. Giant problems: So much for the Giants bouncing back and recovering from last week's collapse against the Eagles. The losers of the Miracle in the Meadowlands II looked like as flat as the mountainless drive across Wisconsin to Lambeau Field. Aaron Rodgers picked the Giants apart for 404 yards and four touchdowns in a 45-17 Packers blowout. Now the Packers have jumped ahead of the Giants for the final playoff spot in the NFC.

Maybe the Giants are a bit of a mirage. People keep saying schedule isn't important, but the Giants could end up losing the playoff spot to Green Bay because they struggled against good teams. Overall, the Giants are 1-4 against teams with winning records, beating only the Bears and losing to the Packers, Colts and Eagles twice.

The concern for Tom Coughlin has to be the defense. The injuries at wide receiver turned the Giants into a two-tight end running team, but that doesn't work when top quarterbacks put up more than 30 points in a game. What should have been a clue is how often they used a "big nickel." The Giants' big nickel uses safety Deon Grant to replace a linebacker, supposedly adding more speed to the defense. Grant showed last week his speed isn't good enough to tackle Michael Vick on blitzes. Whether they make the playoffs or not this year, the Giants will be looking for upgrades on the offensive line and defense.

5. Don't count out the Colts: Those who were giving up the Indianapolis Colts and Peyton Manning for dead better beware. Manning is as dangerous as ever and is on the verge of making the playoffs for the ninth straight year. Sure, the three-receiver offense isn't the same without a legitimate slot guy. Rookie Blair White isn't close to being as good as Austin Collie or Anthony Gonzalez, but somehow Manning pulled out a 31-26 victory over the Oakland Raiders.

The best play of the game came toward the end. Manning had a third-and-2 at the Raiders' 31-yard line with 1:39 left. He needed a first down to win the game. He fooled the Raiders' defense with a 27-yard run, the second longest of his career and his longest since 2001.

If they beat the Titans next week, the Colts are in, mostly likely as the No. 4 seed in the AFC. They probably will face a Ravens team that has some issues at cornerback.

Even though the Detroit Lions upset the Miami Dolphins 34-27, the Washington Redskins upset the Jacksonville Jaguars 20-17 in overtime and the Bears beat the Jets, the AFC won the interconference rivalry 34-30. The AFC is 13-0-2 against the NFC since 1996. … Miami's 1-7 home record probably sealed the fate of head coach Tony Sparano. For the past couple of weeks, people in attendance in Miami have estimated there have been more than 20,000 no-shows. A football town at heart, the Dolphins' poor record and the rise of the Miami Heat have to concern owner Stephen Ross. Understand the market in Miami: the city embraces winners. The Dolphins are 7-8 and fans aren't buying this team, which clearly will affect season-ticket sales next season unless Ross hires a big-name coach such as Bill Cowher or Jon Gruden. The other concern has to be whether fans will buy another season of Chad Henne, who threw the game-losing interception that was returned for a touchdown by linebacker DeAndre Levy with 2:11 left in the fourth quarter. Henne, who is often criticized for throwing too many conservative checkdowns, has watched his interception total rise from 14 in 2009 to 18 this season. … Halfback LaDainian Tomlinson told an amusing story about how the Jets learned they made the playoffs. The Jets' coaches and quarterback Mark Sanchez were watching a television set near a doorway near their locker as the Redskins' Graham Gano lined up for the game-winning field goal against Jacksonville. Tomlinson jumped out of his locker seat and joined Sanchez and the coaches. He said general manager Mike Tannenbaum was praying Gano made the kick. Once he did, Tomlinson walked into a puzzled locker room and said that they were in. A down locker room from the loss to the Bears started to celebrate. … Tom Brady didn't make too many changes to the Patriots' offense even though tight end Aaron Hernandez was inactive for Sunday's easy 34-3 victory over the Buffalo Bills. The Pats stayed in mostly two-tight end sets, but tried a few extra three-receiver plays. Once those formations got the Pats the lead, they pounded the run, getting 217 yards on 41 rushing attempts. … The Jaguars were clearly lost offensively with Maurice Jones-Drew sidelined for the first time in his career with an injury. Minus the running threat, quarterback David Garrard didn't threaten the banged-up Redskins defense even though he threw for 299 yards. Garrard simply couldn't make enough big plays. What was more amazing is how the Redskins held the Jaguars to 17 points minus many key players on D, including starting linebacker Brian Orakpo. … The Titans' 34-14 loss to the Kansas City Chiefs further jeopardizes the coaching future of Jeff Fisher, who is now 6-9 and out of the playoffs. The Titans' defense looked helpless trying to stop the Chiefs. … The surprise of the day was how well the Bengals' Jerome Simpson played at receiver filling in for Chad Ochocinco and Terrell Owens. He had dropped as low as the No. 5 receiver, but he came out of nowhere to catch six passes for 124 yards and two touchdowns in a 34-20 victory over San Diego. … The Ravens think they may have lost long-snapper Morgan Cox for the season with a knee injury. Also, linebacker Tavares Gooden dislocated his left shoulder for the second time this season and tight end Dennis Pitta suffered his second concussion of the season. … There was definite improvement in Tim Tebow's second start for the Denver Broncos. Against perhaps the worst secondary in NFL history (the Houston Texans'), Tebow did more than just throw screen passes and checkdowns in a 24-23 win. A few times he stayed in the pocket and threw completions. His competitive leadership was visible in leading the Broncos back from a 17-0 deficit. … If you're wondering about the draft order, the Panthers have locked up the No. 1 pick thanks to the Bengals' victory over the Chargers.