This weekend's NFL Combine in Indianapolis will have little to do with football. It's part track meet, part job interview, part medical exam, but little pigskin.

	Brian Urlacher led the Bears in sacks and tackles during his rookie season.

Sure, quarterbacks will throw, receivers will catch and running backs will run, but they'll do it without pads and without Ray Lewis licking his chops across the line.

And for that reason, not to mention the fact that players have spent the last two months preparing for the four-day event, NFL scouts and general managers are cautious about how much stock to put in the much-hyped t-shirt and shorts workout.

Most of them insist it's just one piece of a player's puzzle and that a host of other variables -- collegiate accomplishments, personality, reputation and whether they fill a team's need -- will determine where a player is selected.

"This is not football. They're not hitting anyone," said New York Giants general manager Ernie Accorsi. "They're running around in underwear. You have to discipline yourself and remind yourself of that before you go."

But it's not always that easy. Even though a scout may have followed a player for four years, logging hundreds of evaluations, collecting hours of game tape and solidifying his team's stance on a player, those opinions can change in the space of a 40-yard dash or 10-minute interview.

"The reality is there are more coaches and general-manager types that don't have the time to watch all the tape and do all the analysis they should," said one former NFL player personnel director. "And this is a human grading a human. When you sit down with a player, you can't help but be influenced when you see him in person and shake his hand -- especially if you haven't done all your background work."

Even Ron Wolf, the former Green Bay general manager who solidified the Packers' back-to-back Super Bowl trips in the mid-90s through the draft, struggled to keep from being swayed too much by one weekend's workout.

"It's human nature," Wolf told the Denver Post last spring. "The worst thing you can do is alter your opinion based on how high a guy jumps or what he does in the shuttle run. You've arrived at your conclusion watching him play football. Now, all of the sudden, people are changing their opinions."

Which is a dangerous thing to do. For every Brian Urlacher, Kyle Turley or Luke Petitgout, guys who boosted their draft status with impressive workouts and then proved to be solid NFL players, there's a Mike Mamula.

Mamula, a defensive end from Boston College, used the 1995 combine to catapult himself from a projected third- to seventh-round pick into the top 10. At 6-foot-4, 252 pounds, he impressed scouts with a 4.58 40. The Philadelphia Eagles were so enamored with Mamula's performance that they gave up two second round picks to move up from the No. 12 pick to No. 7 to take Mamula in the first round.

Five disappointing seasons later, the Eagles cut Mamula. Soon after, he retired, citing concerns for his health. But he already had been labeled a bust. A workout wonder. And the poster boy for the dangers of relying too heavily on a combine workout.

"It happens every year," Baltimore Ravens vice president Ozzie Newsome said. "We're all guilty of it. We fall in love with the physical ability. They all (look) good in shorts and T-shirts. But you've got to remember, they don't play on Sunday in shorts."

Of just as much concern is the amount of preparation players put into the combine. The explosion of combine preparation facilities over the last decade, in which players spend two to three months preparing for this one weekend, makes it difficult to get an actual reading on their ability.

"They've crammed for this like a final," said Randy Mueller, the Director of Player Personnel for the New Orleans Saints, "so you can't get that excited about some guy's shuttle run.

"But with that, I like the fact that they have the time to prepare. It says something about a guy's work ethic and how he's going to prepare for the season once he's on my team."

It's all part of the chess game. Coaches and general managers are well aware that players not only prepare for the on-field drills and physical testing, but for the psychological evaluations and the 10-minute interviews with representatives from each team.

Most players will sit down with representatives from each of the 32 NFL teams (including the expansion Houston Texans). Teams will inquire about a player's background. His work ethic. His friends. And any mishaps he's had with the law.

Nothing is off limits. But barely anything catches a player off guard. Their agents have prepped them on potential questions and worked with them on delivering the right answers. It leaves the GMs with the challenge of deciphering what's real and what's scripted.

"You have to trust your instincts and perception," Accorsi said. "Most of us have been around enough to see the spin on a curveball. If you can't tell that you're getting conned, you don't belong in the business. You have to look between the words and between the lines."

Said Mueller: "It's a job interview. It's no different than anyone else. If you were a college senior going for an interview at IBM, you'd want to be as prepared as you can be. You'd rehearse the answers, too. But we know this already."

The culmination of all this -- the physical testing, the medical examinations, the interview sessions -- typically boils down to one human emotion for the league's decision makers: Fear. The fear of passing on a future NFL star. And the fear of drafting someone who turns into a bust.

They do all this analysis to squelch those fears. But is it worth it?

"Before the combine, we just went on college production because that's all we had," Accorsi said. "And I'll tell you what -- we hit as many then as we do now."

Wayne Drehs is a staff writer for ESPN.com. He can be reached at Wayne.Drehs@ESPN.com.