EAST RUTHERFORD, N.J. -- Trying to get inside Peyton Manning's head and figure out his genius can leave a defensive coordinator or a linebacker in a straitjacket.
Deciphering his audibles, his body movements and even what the tone of his voice means on his calls at the line of scrimmage is like trying to solve the nation's debt.
"I don't think Peyton knows [himself]," defensive end Justin Tuck said when asked how much Manning is bluffing when he barks out signals at the line of scrimmage. "I have no clue. They said it is a different tone when he is being coy and when he is being for real. I don't know that tone yet."
There are a few players in the New York Giants' locker room who may know all of Manning's subtleties and complexities. Backup quarterback Jim Sorgi spent six seasons as Manning's backup and confidant in Indianapolis. Linebacker Keith Bulluck stared into Manning's eyes and tried to match wits with him twice a season for the past eight years as a division rival with Tennessee.
Whatever those two don't know about Manning, Eli Manning does. The Giants not only have Peyton's former longtime understudy and a former divisional foe on their roster to figure out his brilliance, they have DNA on their side as well.
And then there is safety Deon Grant, who was Peyton's teammate for a year at Tennessee. He knows plenty about the Manning clan.
"I knew about Eli before Eli was Eli," cracked Grant, who was a freshman when Peyton was a senior.
With Sorgi, Bulluck and Eli, the Giants might know if Peyton is a boxers, briefs or boxer briefs kind of guy. But can they find a way to help Perry Fewell's defense get underneath Manning's skin Sunday night in Indianapolis?
"I have a lot of information," Sorgi said of his familiarity with the Colts' offense. "Being there six years, I helped put in a lot of the information that they use. Sometimes how much doesn't really matter. It is all about executing against him. I can give the defense all the information that I can and it is all can we get to Peyton. You can know what route is coming and still not cover it."
Manning was knocked down 10 times during the Colts' season-opening 34-24 loss to the Texans last Sunday. Fewell will try to get to Manning by attacking the Colts with an offensive defense much like he did in the Giants' 31-18 win over Carolina on Sunday. He will move pieces around and probably come up with a surprise wrinkle. In an effort to shut down Carolina's vaunted physical ground game, Fewell started defensive end Mathias Kiwanuka at linebacker and employed packages with three safeties on the field.
But Manning, the only four-time MVP, has pretty much seen everything. The Manning brothers have not only discussed the ins and outs of football with each other, but they often share their experiences and incorporate the ideas of various coaches and players at their annual football camp.
"A lot of it isn't talking football as in teaching," Eli said of his football discussions with big brother. "Sometimes, you talk concepts or something comes up and you're talking football and you may be talking to a coach or you get some college quarterbacks and they start asking questions or throwing some different ideas around or how you work and how you watch film. Maybe you hear something that helps you that you didn't know he was doing."
One thing the Giants have going for them is Peyton's unfamiliarity with Big Blue under its new defensive coordinator. He has only five games (four preseason) of film to study Fewell's Giants' tendencies. He can go back to Fewell's Buffalo days but he really won't know what Fewell will throw at him with the likes of Osi Umenyiora, Tuck and Kenny Phillips.
However, Manning does have a relatively inexperienced middle linebacker to attack on the other side in Jonathan Goff.
Goff is a very heady player and has been studying tons of film on Manning. He has Bulluck to lean on as well. Bulluck spent the past decade with the Titans and saw Manning 16 times since 2002 in the AFC South.
Bulluck's Titans went 5-11 during that span against Manning.
"Honestly, I've played him so much that I know what he is trying to do," Bulluck said. "I know what he is trying to do based upon how their offense works. It is just a matter of stopping it."
Fewell estimates that Manning bluffs at the line of scrimmage 50 percent of the time. Sometimes he is changing the play. Other times he is disguising to throw the defense off.
"It depends on his mood," Sorgi said. "A lot of it is actually changing and signaling. Sometimes it is a lot of nothing. He is so good at playing chess with the defense that he knows when he needs to give them a little something to make them think that he is doing something. Sometimes it means a lot. Sometimes it means very little."
Bulluck says not to believe it's all bluffing and disguising.
"That is not true," Bulluck said when asked if Manning's machinations are just a smoke screen. "He is reading coverages, reading the safeties, reading to see if you are in man, Cover 2, Cover 3; that predicates the calls that he makes.
"In Tennessee, we have known them for a long time and it still doesn't matter," he added. "We have their backup quarterback here for the last six years. That doesn't give us an automatic win. We have to be on point."
And that may be the one thing that Eli, Sorgi and Bulluck all agree on. No matter how well they know Peyton, none of it matters if the Giants can't stop him.
"Peyton is smart enough to know that Sorgi knows everything that he did so he is going to change some things up and give you a lot of dummy calls," Tuck said. "I am sure they are going to [throw] some wrinkles in where maybe one thing meant something and they will say it and it won't mean the same thing. Obviously it is good to have Sorgi and Keith and those guys who have been around Peyton long enough.
"But we have to still go off our p's and q's from what we see on film from them this year."