Belichick's next mission: Prove it's not all about Brady

In December 2007 in Giants Stadium, Matt Cassell (left) and Bill Belichick celebrated the completion of a 16-0 Patriots' regular season under starting QB Tom Brady. Sunday, the duo will try to extend the Patriots' winning ways without Brady. Rich Kane/US Presswire

Now that the worst-kept secret in New England finally has been confirmed by New England Patriots head coach Bill Belichick -- that reigning MVP quarterback Tom Brady needs season-ending surgery to repair his injured left knee -- the next question for this team is obvious: How will Belichick guide the Patriots through the most difficult challenge of his career?

Sure, the Patriots have the pride that comes with three Super Bowl victories in the past seven seasons. They also have a slew of grizzled veterans who have valuable experience. But they no longer have their best player, and that means Belichick must work his magic like never before.

We don't know how good a coach Belichick is when Brady isn't his quarterback. For those who don't remember, Belichick looked exactly like a guy who was working his way out of town before Brady replaced an injured Drew Bledsoe in the second week of the 2001 season. The Patriots won just five games in his first season (2000) at the helm and started the next campaign with two losses. Combine those numbers with Belichick's well-documented failures in Cleveland as the Browns' head coach, and he has a 42-58 record in the NFL without Brady as his starter.

Granted, Belichick is the man who discovered Brady in the sixth round of the 2000 NFL draft. He's also the same coach who carries a well-earned reputation as a defensive mastermind. But superior players often make coaches seem greater than they actually are. Just as Michael Jordan, Shaquille O'Neal and Kobe Bryant turned Phil Jackson into one of the NBA's most revered strategists, Brady clearly has helped Belichick become one of the most sanctified names in NFL coaching annals.

The issue is whether Belichick can maintain such a lofty reputation while relying on a backup quarterback named Matt Cassel, a four-season veteran who hasn't started a meaningful football game since his senior year of high school. The likelihood is that the head coach and the team will struggle. There's no doubt they'll be prepared. They'll also be motivated by comments coming from skeptics like yours truly. But what they won't have is that same self-assurance that comes when you know a star like Brady is playing on your side.

You could see that just by looking at the Patriots' 17-10 victory over the Kansas City Chiefs on Sunday. Though the Chiefs came into that contest as 16-point underdogs, they gained more confidence once they sensed Brady wasn't returning from his first-quarter injury. The Patriots eventually found themselves in a contest that wasn't decided until Chiefs backup quarterback Damon Huard missed wide receiver Dwayne Bowe on a potential game-tying touchdown pass in the final minute.

Just like that, the Patriots went from a cocksure team coming off an 18-1 season to an ordinary bunch of players with an unmistakable bull's-eye on their backs.

Of course, Belichick spun that game as a hard-fought win in the face of tremendous adversity. But it was something else as well. It was evidence of just what the Patriots are when Brady isn't available.

They have a handful of exceptional players -- including wide receiver Randy Moss, left tackle Matt Light and defensive linemen Richard Seymour, Vince Wilfork and Ty Warren -- but they aren't capable of intimidating anybody without Brady under center.

That is why Belichick's job is that much harder today. Brady was the guy who gave New England its aura. Other people can talk all they want about the quality of the Patriots' teamwork and the strength of their collective character. But those things don't mean as much in pro football as a player who can do things other people can't. Brady is that kind of athlete, and he became a more frightening talent with every passing season.

Having Brady on the roster meant that Belichick and Patriots vice president of player personnel Scott Pioli could take chances they might otherwise avoid. They could bring in a Randy Moss and know he wouldn't be a headache. They could dump popular veterans such as Ty Law, Willie McGinest and Lawyer Milloy without fearing the long-term costs.

With a team built around Brady -- who echoed the same concepts Belichick wanted his players to buy into -- the Patriots' brass knew this team could run seamlessly in the face of any circumstance, if for no other reason than he'd make everyone else better.

Now that Brady is out for the year, it's hard to see New England winning more than eight games. The Patriots will have to play a more balanced style of offense than last year's freewheeling, high-flying system, so Moss and fellow wide receiver Wes Welker will be far less dangerous. Their defense also won't have the comfort level that comes with frequent 20-point leads, and their offensive line -- the same unit that the New York Giants dominated in February's Super Bowl -- will face more challenges without the benefit of Brady's quick decisions and even quicker release.

So Belichick can keep telling the public how important it is for his players to simply keep doing their respective jobs. He can talk about how much faith the team has in Cassel and shoot down reports that the Patriots are searching for another veteran quarterback. What he can't do is make us believe that the stoic expression he maintained during Monday's news conference is proof that he's not shaken by Brady's injury. If Belichick's track record before Brady tells us anything, it's that this head coach has plenty to prove in the next few months.

Jeffri Chadiha covers the NFL for ESPN.com.