By Jonathan Comey
Cold, Hard Football Facts Hailer to the Chief
Was Kansas City's breakout 2010 season truly a breakout? Or are they one-hit wonders, the football equivalent of early-90s novelty act Right Said Fred, proving to be too sexy for the AFC West but without much staying power?
It's a tough call. They've got the closest thing to Barry Sanders in Jamaal Charles, a QB in Matt Cassel that was third in our brand-new Real Quarterback Rating (which takes into account sacks, fumbles and rushing yards, as well as passing stats), a stud pass rusher in Tamba Hali and a pair of great corners with the same first name (that'd be Brandon).
And yet, a closer look at their 2010 shows a team that took what the NFL schedule gave them (a league-low three games vs. Quality Opponents) and not much more.
Kansas City
The 2010 storyline: The Chiefs were a great team ... when they were playing the NFC West. Against the Seahawks, Rams, 49ers and Cardinals, they went 4-0, averaged 32.8 PPG, allowed 15.0, piled up an average of 423.8 yards of offense and generally looked like men vs. boys. 
Against the rest of the league, they were 6-6, scored 19.6 PPG and allowed 21.7. They were dominated in three of their four games vs. Quality Opponents (including playoffs), beat only one winning team all year (the 9-7 Chargers, way back in Week 1) and lost four of their last nine games by 20+ points.
Glass half-full? Glass half-empty? It might have been a good season in KC compared to the horror shows of the latter part of the decade, but the bottom line was a 17th consecutive season without a playoff victory.
The Vital Signs
2010 record: 10-6 (17.7 PPG – 26.6 PPG)
Record vs. Quality Opponents: 1-2 (10.0-21.3)
Last five seasons overall: 29-51 (.363)
Best Quality Stat in 2010: Real Quarterback Rating (3rd)
Worst Quality Stat in 2010: Passing Yards Per Attempt (23rd)
All Quality Stats 
Defensive Passing YPA: 5th
Quarterback Rating: 3rd
Defensive Quarterback Rating: 8th
Defensive Passer Rating: 8th
Relativity Index: 16th
Statistical curiosity of 2010
Matt Cassel didn't just like Dwayne Bowe when it came to touchdown passes, he loved him. Bowe had 15 touchdown catches, while the rest of the Chiefs wideouts (Dexter McCluster, Chris Chambers, Terrance Copper and Verran Tucker) combined for three. 
Best game of 2010
42-20 win vs. Jacksonville (Week 7). This was really the Chiefs' only excellent performance against a decent team. They won the turnover battle 3-0, ran for 236 yards and exploded for 28 second-half points to break open what had been a tight game.
Worst game of 2010
31-0 loss at San Diego (Week 14). Their playoff loss to Baltimore was bad, but they suffered one of the worst losses by any 10-win team in history against the Chargers. San Diego outgained KC by 359 yards (426-67) and produced 20 more first downs (25-5) in a 31-0 win that could have been much worse had the Chargers not turned it over twice. 
Secondary. Teams passed against Kansas City an awful lot in 2010 (581 attempts, seventh most), but no one had a net 300-yard game against them. The Chiefs were fifth in Defensive Yards Per Pass Attempt and eighth in Defensive Passer Rating.

They probably weren't quite as good as those numbers would indicate thanks to their soft schedule. But all signs point to the back four being the team's hallmark going forward.
Corner Brandon Flowers was probably the best corner in the league in the first six weeks of the year before an injury caught up to him (and Darrelle Revis recovered from his hamstring problems). While he's only the second-most famous Brandon Flowers on Earth behind the lead singer of The Killers, he's one of the five best cover corners in the league. On the other side, Brandon Carr was consistently good – he was whistled for only one penalty all year.
Even more exciting was the emergence of two rookie safeties as starters – No. 5 overall pick Eric Berry and fifth-round pick Kendrick Lewis. Berry got better as the season progressed, while Lewis fought through injury to more than hold his own. Carr and Flowers are both in the last year of their contracts (Carr was tendered), and expect keeping both in the fold to be one of Scott Pioli's No. 1 goals once football resumes its sanity.
Downfield passing game. Cassel was brilliant in the short game, turning a Tom Brady-esque season with 27 TD against just 7 INT, while Dwayne Bowe made some big plays. But the Chiefs threw deep as rarely as any team in the league, and with as little success. They had only 18 pass plays of 25+ yards, third fewest in the league, and only Bowe had a play of 40+ yards.
The team was third in Real Quarterback Rating, thanks to mistake-free football from Cassel. But they were also just 23rd in Passing YPA. It's rare to see such a vast difference between rating and average per attempt.
The addition of TE Tony Moeaki and RB/WR Dexter McCluster give the Chiefs some exciting short options. But the lack of a deep threat to run some fly patterns and give the inconsistent Bowe some support clearly had an impact on their ultimate success.
General off-season strategy/overview
The Chiefs are in splendid shape free-agent wise. Their only key guy at risk, Tamba Hali, is wrapped up with a tag, and they have one of the five lowest cap numbers in 2011 dollars currently allotted.
So, they can continue to add supplemental players behind their front-line talent and continue to build a winner. Offensive cohesion was a key for the Chiefs; only the No. 2 wide receiver spot had a rotating cast of characters in 2010. The offensive line was intact all year, with only two games missed, and Moeaki was a real find (47 catches, 556 yards, 3 TD for the rookie TE).
Look for veterans like Thomas Jones, Mike Vrabel and Casey Wiegmann to play much smaller roles in 2011 (if they're still on the roster)
Totally premature 2011 diagnosis
Kansas City's easy schedule in 2010 is not repeating itself. Check out the team's eight road games: the annual divisional trips to San Diego, Oakland and Denver, along with visits to Chicago, Detroit, New England, Indianapolis and N.Y. Jets. If this team can even go .500 in those games it would be a minor miracle, and they'll have San Diego, Green Bay and Pittsburgh coming to KC.
Charles is an absolute monster (a Jim Brown-esque 6.4 YPA on 230 carries in 2010), and there's a lot to like here. But the Chiefs were more like an 8-8 team that finished 10-6 in 2010, and they'll probably be like a 10-6 team that finishes 8-8 in 2011. But there's not a lot of 4-12 in their future, that's for sure.