Forget what you saw against the Buccaneers in the preseason.

Forget about the aggressive, attacking unit we wrote about during training camp.

What you saw yesterday in New England’s 31-19 victory over the Raiders at O.co Coliseum, is about as good as it’s going to get.

The bend-but-don’t-break zone is back, baby - for now.

Especially if linebacker Jerod Mayo misses the feared month with a sprained MCL in his left knee, as a league source said.

He’s the heart and the brains of this defense, which appeared to lack both at times this season even when Mayo was in the lineup. But hope still floats that at some point the Patriots will be able to do some more things on defense to dictate the game.

If this team is going to go on a run to the Super Bowl, that will have to happen. To have Super Bowl aspirations, you must affect the quarterback on a regular basis, and get off the field on third downs.

Right now the Patriots are still doing neither.

When you get to the final eight in the postseason - a place the Patriots haven’t been since 2007 - hoping that the Jason Campbells of the NFL make admitted “bone-headed’’ decisions to throw it right to you in the end zone is not a sound point of emphasis in the game plan.

The quarterbacks in this league are way too good to pin your hopes on that.

Sure, it will work in the regular season and you can win a lot of games that way - and the Patriots have and will continue to do so. But in the postseason, when every drive becomes important, quarterbacks are going to beat you a lot more than they’re going to screw up if you let them sit in the pocket.

The Patriots are content, right now, to let them do that. They almost don’t have a choice.

The lockout, preseason injuries, and a growing in-season injury list have forced them to do that.

Bill Belichick had to scrap his plans for an attacking 4-3 defense. After watching his vision get roasted by Chad Henne, Philip Rivers, and Ryan Fitzpatrick, Belichick made the wise choice to go back to more zone coverage.

“We just felt that was the best way in some cases to play Oakland,’’ Belichick said. “But we mixed it in, or tried to, anyway. And we’ll do that week to week. We’ll try to do what we feel is best for our team against whoever we’re playing and gives us the best chance to win.’’

Some of it had to do with injuries. The line, minus projected heavy contributors (no pun intended) Albert Haynesworth, Mike Wright, and Myron Pryor, has fallen short of quarterback pressures. Belichick’s cornerbacks were just not good enough fundamentally to play man coverage. Or maybe they just aren’t capable beyond rookie Ras-I Dowling, who has done nothing to shake the injury-prone label that has followed him since high school. The safeties, especially when Patrick Chung was out last week against Buffalo, also didn’t come close to executing enough to play their role in man coverage. So against the Raiders, the Patriots went back to their security blanket: zone coverage. And you could almost feel the relief that washed over the embattled secondary.

“It’s definitely beneficial,’’ said cornerback Kyle Arrington. “When it comes to a zone, the communication is better because you don’t have to worry about as much motioning and the personnel the opposing team has in the game. I think it benefited us.’’

Going back to zone allowed the new faces in the secondary to keep the plays in front of them, instead of always being a step slow against receivers who make money beating man coverage. It still wasn’t pretty.

Tight end Kevin Boss, especially, helped the Raiders to kill the Patriots with pass plays over 20 yards, but at least there weren’t blown coverages and missed tackles as there were against the Bills (save Sergio Brown’s complete whiff).

And the Raiders still converted 8 of 13 third-down opportunities. But there was some improvement on the field. Holding the explosive Raiders to just 13 points until there was 28 seconds left is not a bad day’s work.

“It was just a little bit more settled in the back,’’ safety James Ihedigbo said. “We always play with confidence but it was just easier for us to communicate, get everybody lined up and play ball and play fast and that’s what we did. It [stinks] to give up that last touchdown, but besides that we played a lot better in the red zone and we executed on defense.’’

After the embarrassing performance in Buffalo, the Patriots were pushed hard by Belichick last week.

“I think it really started in practice,’’ said cornerback Devin McCourty. “We practiced hard and we’ve made plays in practice and communicated well in practice. Like Coach says, when we’re able to do that, it will continue to show up on Sunday. As long as we keep improving in practice, it will show up on Sunday.

“You’re not always going to be happy with your performance like last week, but can you go back and fix it? I felt like as a defense we put that in our head that we’re going to fix it, we’re going to get better. I think we got better.’’

It’s going to have to get much better if this team wants to win in the postseason. It’s going to be hard to deal with Mayo being out of the lineup, but Gary Guyton, Brandon Spikes, and Dane Fletcher will have to get the job done.

“He’s our top defender,’’ Vince Wilfork said of Mayo. “Any time you have your top defender on the field, the better your chances to win. We wanted to keep rolling and we will. It’s an opportunity for different guys to step up. That’s what is going to have to happen right now.’’

Down the road, when Mayo, Haynesworth, Leigh Bodden, Dowling, and Wright return, and when Ron Brace and Brandon Deaderick come off the physically unable to perform list, this defense will have a chance to do some of the things it planned on before the season. It’s going to have to in order to win in the postseason. But for now, what we saw yesterday is going to have to do. It’s as good as it’s going to get.

Greg A. Bedard can be reached at gbedard@globe.com. Follow him on Twitter @GregABedard