New England has some weaknesses, however, that might allow them to be a better matchup for Carolina than San Francisco.
Let's start with the defense, the former pride of the Bill Belichick regime but more recently sagging. Now more of a 4-3, the Pats still provide a lot of double looks, but have scrapped some of the mixed one gap/two gap fronts with some catastrophic injuries in the middle. Mainstay DL Vince Wilford and Ty Warren are both out; behind them, $10 million linebacker Jared Mayo is also out. So what's left?
They've built the rest around Brandon Spikes at MLB, pushing massive OLB Donta Hightower to WLB to cover Mayo, and fellow 2012 rookie Chandler Jones (8.5 sacks) is in front of him at right defensive end. Undersized Rob Ninkovich plays the other end; they've gotten surprise ability out of Bowling Green rookie DT Chris Jones, who has 5 sacks, 3.5 in the last three weeks. He and Joe Vellano, another rookie, start inside, but Vellano subs out for the pass.
Which, that's part of the thing with this defense, it doesn't matter as much what the base is. The Pats sit in nickel 63% of the time anyway, sometimes pushing Hightower to end and Chandler Jones inside him. They have Andre Carter, still in the league, as a sub-in guy, too.
It works well when ahead - powered by the tricky option-rush blitz schemes and CBs Aqib Talib/Alfonso Dennard and nickel veteran Kyle Arrington. The Pats are 12th in passing yards, their best in years; they're 3rd in INTs, and 9th in net yards per attempt, and that's with getting Talib back this week after absence. It can be hard to beat if you live by the pass.
Carolina doesn't. That's where the injuries tend to hurt - and Carolina's solid rushing offense comes in to face New England's 30th ranked rush defense. And they certainly don't get better at stopping the run in nickel, which should be a matter to notice for the 3 WR sets. As well, it might be an unseasonably good time to go 22 personnel - except Ben Hartsock appears to be hurt for this week, leaving it to possibly Richie Brockel - for both run and pass sets, where the Pats are thin inside and without good depth, but it pulls another DB off the field. Carolina can still generate decent passing opportunities with the Cam Newton playaction game and have Steve Smith/Greg Olsen and a back in a pattern with max protect.
But, you can't be scared of these DBs, either; NE has a #1 rating by footballoutsiders.com on the #1 receiver, but 32 against the 2, and 20 against the 3rd. There's room to work.
On the other end, the Panthers get similar breaks with the Pats' offense. OC Josh McDaniels has brought a stronger rushing attack to the Ehrhart Perkins attack than his first stint, and a few of the spread type elements have dwindled, but it's still the same type attack with more rushes. The Pats come in as the 5th yardage rush offense (11th in yards/attempt), so in its ideal form, it's an offense that can run out the clock just as easily as it can hit you with 80 plays and 30 points. But it's a matchup offense that might work in the Panthers' favor, with its stout defense.
Carolina penetrates the zone runs easily, and New England essentially uses an inside zone, an outside zone, and counters on those plays. They should have some success against Carolina, but if things go as they have recently, Carolina should overpower the front and leave the Patriots one-dimensional.
Tom Brady's showing some age - chinks in the armor - or he's struggling with the changes, depending on your viewpoint. But he's not up to his usual standards. His yards per play are lowest since 2002, and he's already taken as many sacks as the entire 2012 season. His 82.9 QB rating isn't bad, but it's his lowest total in a full season ever. He still doesn't turn the ball over, but he's not quite what he was. The last good defense he faced, in an OT loss to the Jets, he averaged 5 yards an attempt and a 47.8 percent completion percentage (which included having TE Rob Gronkowski).
He's been without Gronkowski for most of the year (unfortunately for Carolina, he's back), has had to exchange Wes Welker for a less durable Danny Amendola, and hasn't had outlet Aaron Hernandez for obvious reasons as well. Julian Edelman leads the team in receptions, though rook Aaron Dobson has shown the ability to make plays Edelman hasn't. Amendola is a solid slot receiver, but he's not Welker. The powerhouse is Gronkowski, and 2nd TE Michael Hoomanawanui is just a big blocker. The others, you have to show covered and contest the ball more - they're crafty - but Gronkowski is the guy you have to have accounted; in two of his three games back, he's caught 8 or more balls and over 110 yards. He caught 10 or more TDs in every prior year, and he could make it this year with limited time if he stays healthy.
So, if you can stop the Pats' running game, that's what you get to face. Gronkowski, a hard guy to stop on a good day.
Still, first you do have to set out to stop that running game. Stevan Ridley looked to be losing his job to Shane Vereen - then Vereen almost immediately got hurt. So, Ridley's been the motive power behind that 8th ranked rush defense. Ridley is not a pass threat, but at a 4.4 yard average, he's getting it done and he leads the team in total touchdowns with 6. LeGarrette Blount is listed at FB and gets the balance of the carries. Not much on tricks, the Patriots have given three rushes to wide receivers.
Where that run game really happens? The OL. They have some pass weaknesses, namely Dan Connolly, but Nate Solder is playing like a top LT, and Logan Mankins isn't letting up to his right. Massive RT Marcus Cannon (6'5, 345) takes over for the more fleet footed Sebastian Vollmer - this will be his third start of his career, but he gets push in the run game and makes for a wide body to get around.
If New England gets one-dimensional, I don't know if that helps Carolina the way it would playing other teams. But Carolina has proven to be OK against 3 WR, and it's been a while since that defense has shown major problems. Bracketing Gronkowski and stopping the run seem like the obvious ways to go - and if it becomes a battle of field position, Carolina's playing that well. They probably would struggle in a shoot-out, and it's been a few weeks since much magic happens in Carolina's passing game.
But the matchups seem to go in Carolina's favor in this one. They would have to force the Pats to play their game, but it's doable, and if so, it's a win.