How vulnerable is Tom Brady?

Tom Brady is considered the best quarterback of this era, a sure first-ballot Hall of Famer and a fierce competitor who doesn't back down in pressure situations.

Yet since the Patriots' loss to the Giants in Super Bowl XLII and his recovery from a knee reconstruction the next season, Brady no longer seems invincible. Opponents with the ability to rush the quarterback believe they can get to him both physically and mentally.

"I think it starts with hitting him,'" Giants defensive end Justin Tuck said. "Even when you don't actually get sacks, just keeping people around him so he can't step up. I think he gets a little frustrated when he has to go to his second or third receivers. You can kind of confuse him sometimes with our coverage. I thought there are a lot of things that can get him rattled, but it just seems like not too many people are able to do that.'"

The Detroit Lions exposed Brady's vulnerabilities in the preseason. Other teams sprinkled in successful defensive schemes that affected him at times during the season. The concept that appeared to work best was using enough man coverage on the pass-catcher to disrupt timing and separation and then augment that with getting defenders around Brady's feet.

The Giants possess three great pass-rushing defensive ends -- Tuck, Osi Umenyiora and Jason Pierre-Paul -- and thus have the type of defense that could disrupt Brady in Super Bowl XLVI. Those three ends have combined for 30.5 of the Giants' 48 sacks and pose big problems for the Patriots' offensive line. At times, the Giants attack with four defensive ends.

"We have to be aware that they're all in there for the speed,'' Patriots guard Logan Mankins said. "The line has to know what's coming and what they can do with those four guys and just be up to the speed of the game that they're going to bring in there.''

Like most quarterbacks, Brady likes a clean pocket. He has a slide step that allows him to buy extra time to release a pass, but if the step isn't there, he tends to rush throws and get frustrated. He'll get in the faces of his blockers if things don't go right.

The Giants got to him in their last Super Bowl meeting.

"We had a lot of hits on him,'' Tuck said. "Even when we didn't hit him, he didn't have the time to sit back there and allow some of the routes to develop. We know that as a D-line, we put a lot of pressure on ourselves to make sure that we are in his face. He is a hell of a quarterback, and he is going to do a lot of things to throw us off our rhythm. I really expect them to use their screen game, quick throws, to kind of get us out of our game early.''

Brady didn't use the screen pass a lot during the regular season. According to ESPN Stats & Information, Brady tried screen passes 45 times. He completed 73 percent of the throws, but many of the screens weren't effective. His Total QBR rating on screen passes was 18.3, one of the lowest in the league.

The high ankle sprain of tight end Rob Gronkowski may take the Pats out of the two-tight end, three-receiver offense and force them to use a running back more and occasionally try a screen.

All the Giants know is that they have to get their four-man line to pressure him.

"It doesn't matter if he had surgery or not,'' Tuck said about whether Brady worries about reinjuring his knee under a hot pass rush. "As an athlete, you don't want anybody around your legs. As a D-lineman, I don't want O-linemen cutting me. I'm sure as a quarterback, you don't want guys diving at your knees either. I'm sure that would find a way to get to his psyche a little bit, but I don't think it has anything to do with him just being a quarterback. I think it has a lot to do with just athletes in general.''

Tuck and Brady's blockers don't get along especially well, and that gets worse the more they meet. Tuck thinks Patriots blockers get around the legs of defenders too much and calls them dirty.

"That's all right, we don't mind being called dirty or cheap or any of that stuff,'' Mankins said. "That's a compliment to us.''

The Giants sacked quarterbacks 34 times when rushing four or fewer defenders, second only to the Philadelphia Eagles, according to ESPN Stats & Information. Rushing four allows the Giants to drop seven defenders into coverage to confuse and frustrate Brady.

But when the rush doesn't get to the quarterback, the Giants are vulnerable. The Giants gave up 3,195 yards when the four-man rush didn't get to the quarterback. That's the fourth-most in football, according to Stats & Info. The 18 touchdowns allowed is the seventh-highest total.

"It seems whomever they put in there can get after the quarterback,'' Brady said. "Anytime you can limit the quarterback from the time it takes to make a read to make a throw, it's much more challenging. It comes down to quick decision-making. I put a lot of trust in my offensive line.''

John Clayton, a recipient of the Pro Football Hall of Fame's McCann Award for distinguished reporting, is a senior writer for ESPN.com. Follow Clayton on Twitter