The Patriots' quarterback has the innate ability to exploit weaknesses and mismatches in a defense like few others in the NFL. Getting back tight end Rob Gronkowski, one of his primary targets, makes him that much more of a threat.
The Panthers know that. "Tom Brady is one of the most dangerous quarterbacks in the league," linebacker Thomas Davis said.
Brady is particularly dangerous on "Monday Night Football," where he is 13-4, and has won five straight and 10 of his past 11. He has thrown three or more touchdowns in Monday night's showcase nine times.
But Brady will encounter his own X factor: the Panthers' defense, which has given up only seven touchdown passes and made 13 interceptions, and is holding opposing quarterbacks to a QBR of 30.3 -- the second-lowest figure in the league. The league average is 51.2. Brady's mark is 56.9.
The average passer rating against Carolina is 74.6, fifth-lowest in the league. The league average is 86.4. Brady's mark is 82.7.
So while Brady versus most defenses is a mismatch, the Panthers have a chance to negate that if they play at the level they have been during a five-game winning streak -- and really most of the season.
"Tom Brady sets up everything when it comes to their offense," rookie defensive tackle Star Lotulelei said. "If we take away that, we have a much better chance."
Carolina has its own quarterback on defense in middle linebacker Luke Kuechly, named the NFC defensive player of the week for his effort in Sunday's 10-9 victory at San Francisco. Kuechly helped the Panthers hold Colin Kaepernick to a QBR of 7.7, his worst of the season, more than 50 points below his average and more than 90 points lower than what he'd put up in each of his previous two games. They sacked him six times and held him to 91 passing yards.
Kuechly doesn't look at the challenges Brady presents any differently, although Kaepernick is much more mobile. That's because the game plan is pretty much the same -- stop the run, pressure the quarterback and force turnovers.
"I look at it just as a team that has a good quarterback that is going to be a challenge for us," Kuechly said. "[Brady's] a smart guy. He's like Peyton [Manning] in the aspect he's going to get his team in a situation that is going to be beneficial for them. We need to do a good job of playing in our defense and not showing stuff too early so he can get a bead on what we've got."
If that happens, Brady will do to Carolina what he does to every other defense.
"If he finds out what we're in, he'll pick us apart," cornerback Captain Munnerlyn said.
One of Carolina's strengths is not showing what is in. The defense can do that because it can disrupt the run and rush the quarterback with four down linemen most of the time.
The X factor within the X factor is Gronkowski. Since returning from back and arm injuries, he has been targeted 10.7 times per game, the most in his career. He had nine catches for 143 yards and a touchdown in the 55-31 victory over Pittsburgh. Brady, by no coincidence, had his highest QBR (97.7) and passer rating (151.8) of the season in that game.
The previous time the Panthers faced a tight end of this caliber was two games ago, when Atlanta's Tony Gonzalez had five catches for 77 yards and a touchdown in the first half. He had one catch for 4 yards in the second half.
"Just straight adjustments," said Gronkowski, who has studied the Atlanta film. "They know how to adjust on the fly. They know how to adjust coverage. They're overall a great defense."
That shows up in the statistics. So while the Patriots have a quarterback who can adjust as well or better than any in the league, the Panthers have a defense that can do the same.
X factor versus X factor.
Maybe they should call this the X Game.