Being a cornerback, Tramon Williams gets tested every game.
In 2010, Williams passed nearly every exam for the Green Bay Packers, producing a league-leading total (including the postseason) of nine interceptions, earning Pro Bowl distinction and winning a ring for Super Bowl XLV.
Off the field, he's a quick study, too.
Last week he was asked to list the criteria that make for a championship team.
"Hmm," he said from the Packers' facility in Green Bay. "First of all, most championship teams have an elite quarterback. No. 2, the defense will be playing well. Three, the team will be playing well at the right time of the season."
Those were the top three categories -- in the exact order -- ESPN.com came up with after days of talking to folks around the league and examining the numbers of the 10 previous Super Bowl champions.
"It's just the facts of life in the NFL," Williams said. "You're going to have growing pains, but at some point it's going to come together. End of November, December, if you're playing well at that time, oh, man, the sky's the limit."
Here, based on the season's first half (or, in some cases, one game less), are the 10 teams who meet all or most of those critical criteria of a squad destined for the bead-tossing madness of Bourbon Street and Super Bowl XLVII:
Atlanta Falcons (7-0)
They are the only team that still poses a threat to those feisty 1972 Miami Dolphins, who finished 17-0.
Even without a championship victory on their résumé, history tells us the Falcons have a better than 25 percent chance to win the Super Bowl, 50 percent to reach it and 95 percent chance to make the playoffs. Of course, given the recent experiences of top seeds, maybe they should ease off the gas.
All the components are here: Matt Ryan is not widely acknowledged as an elite quarterback, but with 17 touchdown passes, six interceptions and a passer rating of 103.0, he's making an argument for himself. He also has an able cast of characters, particularly at receiver. Atlanta is 4-0 on the road and has a terrific turnover ratio of plus-10, fourth in the league.
Houston Texans (6-1)
The defense is among the league leaders in fewest points allowed (18.3), net turnovers (plus-7) and sacks (21). Kicker Shayne Graham is 13-for-14 in field goals and has scored 64 points. Houston is also a sparkling 3-0 on the road, including a win at Denver.
No, nine-year veteran quarterback Matt Schaub is not an elite quarterback, but he's been very efficient, completing 63.1 percent of his passes and throwing 10 touchdown passes. His interception percentage (a minuscule .018) is among the league leaders. And the Texans have protected him, allowing only eight sacks in seven games.
In the 11th season of their existence, the Texans have the right stuff to find themselves, come late January, eating in one of Emeril Lagasse's three spectacular restaurants in New Orleans.
New York Giants (6-2)
Two Super Bowl wins in the past five years make them legitimate championship contenders.
The offense is one of the league's best units. The quarterback has put the Eli in eli-te. Manning's fourth-quarter numbers are unmatched, and the Giants' plus-13 turnover differential is tied for best in league.
Admittedly, the defense has given up a ton of yards, particularly on the ground, but in the critical areas, it's still in the game. The Giants have forced 24 turnovers, the league's best total. They are also third in fourth-quarter point differential at plus-42.
The Giants are 3-1 on road and, including the playoffs, have won seven of their last eight away from home. Kicker Lawrence Tynes leads the NFL in scoring (94 points) and is 24-for-26 in field goals.
San Francisco 49ers (6-2)
Last season, there were times when Alex Smith actually looked like the first overall choice of the 2005 draft.
Under the tutelage of head coach Jim Harbaugh, Smith had a passer rating of 90.7, completing 61.3 percent of his passes. More importantly, he only threw five interceptions, compared to 17 touchdowns. This year, with some more firepower (hello, Mario Manningham and Randy Moss), he's continued to improve. This is critical, because last year's NFC Championship Game came down to Eli Manning outplaying Smith.
The defense, of course, is lights out. The 49ers lead the league in defense in terms of yards allowed, and they also allow the fewest points points per game (12.9).
Chicago Bears (6-1)
You can see the gleam in their eyes, the scouts say, when they make tackles. Their hands are always attacking the football.
The Bears are second in the NFL with 23 takeaways, including 16 interceptions. They forced four turnovers against the Detroit Lions a week ago on "Monday Night Football." They are the league's top team in fourth-quarter turnover differential (plus-7) and third in overall turnover differential (plus-12).
Quarterback Jay Cutler, at times spectacularly good -- and bad -- has been efficient, but with this defense he can afford to stop forcing things. The Bears need to protect him better (25 sacks, one of them a brutal slam-down by Detroit's Ndamukong Suh), but they have the players to do it when (if?) Cutler learns that giving in -- throwing the ball away on occasion -- doesn't necessarily mean giving up.
New England Patriots (5-3)
A good offense can go a long way toward compensating for a lousy defense. But can it be enough to get you to the championship game?
Yes, as the Patriots showed last year. Tom Brady's offense was ranked No. 2 in terms of yards, while the defense was second-to-last by that yardstick. But ... New England was also the AFC leader with 34 takeaways and produced the conference's best net turnover number at plus-17 -- 10 better than No. 2 Houston.
Certainly, Brady (owner of three Super Bowl rings) isn't producing the crunch-time numbers of his youth, but at 35 he is increasingly wiser. His interception percentage (.009) is the lowest in the league. The Patriots are tied for first in turnover differential at plus-13.
Again, the defense is shaky -- but opportunistic. New England was outscored 34-6 in the fourth quarter of Weeks 5-7 but is tied for second in the league in fourth-quarter turnover differential, plus-6.
Green Bay Packers (5-3)
The Packers have overcome injuries before, so cornerback Charles Woodson's broken collarbone shouldn't be of great concern. He'll likely come back after six or seven weeks and, going forward, the Green Bay secondary will be deeper for it.
Aaron Rodgers, the Super Bowl XLV MVP, has the league's second-best passer rating (107.9), and his 21 touchdowns and four interceptions leave him with the best differential there, plus-17. Rodgers threw for at least three touchdowns a game in four consecutive games this season. Since he became the primary starter in 2008, he's had 28 such games. Only Drew Brees has more in that time.
The Packers' defense is mediocre in yards allowed but dangerous in sacks (a league-high 26) and forcing turnovers in the fourth quarter (four).
Denver Broncos (4-3)
No team illustrates the value of an elite quarterback like this one.
With Tim Tebow under center last season, the Broncos made the playoffs and even beat the Steelers in a wild-card game. But with a berth in the AFC Championship Game on the line, they fell to New England 45-10. Raise your hand if you think Peyton Manning -- even at the age of 36 -- can help achieve a different outcome.
The Broncos, who already had a pretty good defense, suddenly have an offense. Manning, the MVP of Super Bowl XLI, has thrown for 17 TDs with four interceptions and has a passer rating of 109.0, best in the league. When the Broncos have been behind in the second half, he's even better (nine touchdowns, zero interceptions). Denver leads the league in fourth-quarter point differential (plus-73) by a wide margin.
Pittsburgh Steelers (4-3)
With three Super Bowl appearances in the past seven seasons, they certainly have recent history on their side.
And, with quarterback Ben Roethlisberger (two rings), they'll always have a chance. This season, despite all kinds of injuries around him, he's produced a passer rating of 101.4 to go along with 14 touchdown passes and only three interceptions.
The defense has some work to do. It is ranked No. 2 in fewest yards allowed but is not among the league leaders in points allowed (20.6), sacks (12) or takeaways (7).