BALTIMORE (AP) There once was a time when Ray Lewis served as the centerpiece of the best defense in the NFL.
That role is now being played by Zachary Orr, the Baltimore Ravens middle linebacker and leading tackler on a unit ranked No. 1 in the league.
Though the names have changed, the philosophy behind the Ravens' defense remains the same.
So does its effectiveness.
The current edition of the Baltimore defense is not yet worthy of being compared some of the great ones of the past, most notably the 2000 version, which set a record for fewest points allowed in a 16-game season before winning the Super Bowl.
But entering Monday night's game against the New England Patriots, the Ravens (7-5) are in the mix for the AFC North title on the strength of a defense that has limited the opposition to an NFL-low 73.8 yards rushing per game.
''They're the first-rated defense in the league, so no one has done a better job over the course of the season than them,'' Patriots quarterback Tom Brady said.
''They don't give you anything easy. You have to earn it. They do a good mix with their scheme and also with their personnel.''
The plan hasn't changed much since Lewis arrived in Baltimore in 1996. While the tackles jammed the front of the line, Lewis honed in on the guy with the ball. In case of a pass, safety Ed Reed had Lewis' back.
Tony Siragusa, Haloti Ngata, Kelly Gregg and several others played front man for Lewis, who retired after Baltimore beat San Francisco in the 2012 Super Bowl.
This season, the 335-pound Brandon Williams is paving the way for Orr.
''He is in the middle of the defense,'' outside linebacker Terrell Suggs said. ''That is the heart of it, if you ask me.
''For a long time around here, we had the great Ray Lewis, but nobody ever really mentioned Kelly Gregg and the dominance that he had. Our middle linebacker and our nose guards, that's pretty much the source of our defense.''
Dean Pees has followed the practice of former Ravens defensive coordinators Marvin Lewis and Rex Ryan in utilizing that sound strategy.
With Williams up front, Orr in the middle and three-time Pro Bowl safety Eric Weddle in the back end, Baltimore has allowed only 17.3 points per game.
''We know how we want to play fundamentally,'' Pees said. ''You just have to play that way.''
Now in his fifth season as Ravens defensive coordinator, Pees knows how to put together a unit and make it work.
''We're sitting at the top of the league right now because of the things he's been doing,'' cornerback Jimmy Smith said.
Last week's 38-6 rout of Miami was one of those rare afternoons when both the offense and defense were clicking in unison. If the offense continues to improve, so will the defense.
''I'll tell you this: Our defense is going to look even better if - and when - our offense goes out and puts up points,'' Smith said, ''because we can start playing the defense where we can get after a lot of guys, pin our ears back, get sacks and a lot more turnovers.''
The Baltimore offense should be tested by the Patriots, who in turn know they'll have to be at their best to score on the Ravens.
Asked what concerned him most about the Baltimore defense, New England coach Bill Belichick said, ''Pretty much everything. Tough to run against, very good on third down, don't give up a lot of points, turn the ball over.
''You just can't be sloppy around this defense. You have to take good care of the football and you've got to be physical with them. They've got some big, strong guys up front.''
It's been that way for a long, long time. Just ask Orr, who entered the weekend tied for fourth in the NFL with 112 tackles.
''I have great players around me that have allowed me to flourish in this system,'' Orr said. ''It's probably the best situation I could be in.''
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