Khalil Mack has been one of the best edge rushers, if not the best, in the NFL over the last five seasons. When the Bears acquired the 3-4 outside linebacker from the Raiders just before the season opener, they added to an already stout defense.

He will be the defender the Eagles circle most in their preparation for Sunday’s playoff matchup in Chicago, but locating Mack will not be easy. He lines up almost equally on both sides of the formation, sometimes inside, and will occasionally drop into coverage.

“They’ll move him around, he’ll be on the right, be on the left, be inside. They’ll do a lot of different things with him,” Eagles offensive coordinator Mike Groh said. “Obviously, he’s an elite pass rusher, which we faced a few of those guys this year.”

The Eagles have had great success in neutralizing top defensive linemen, including Mack, over the last two seasons. In the last month alone, they have kept the Cowboys’ DeMarcus Lawrence, the Rams’ Aaron Donald, and the Texans’ J.J. Watt in check.

Right tackle Lane Johnson had a lot to do with Lawrence and Watt being held to no sacks, and he did the same last season when Mack was with the Raiders. But Mack lined up almost exclusively on the left in that game and last year (80 percent). This season, his season split is 52-48 left-right.

Defensive coordinator Vic Fangio has used movement to get the Bears’ other edge rusher, Leonard Floyd, matched up against right tackles, but also to keep offenses that are keyed on doubling, chipping or sliding protection toward Mack guessing.

Johnson and left tackle Jason Peters will be most responsible for containing Mack. The former, after a slow start, is playing at his usual all pro form. The latter has battled through injury and struggled to finish games, forcing Halapoulivaati Vaitai into the lineup, but he’s still a top-tier blocker.

“They’re obviously a huge part of the what we do,” Groh said. “J.P. and Lane have been doing it at a high level for a really long time. They are one of the big reasons for the success we’ve had. Every team can’t sit here and say that they have two bookend tackles like that.”

But it will take a team effort, from the rest of the offensive linemen and the tight ends and running backs, to quarterback Nick Foles and the coaches, to keep Mack from wrecking the Eagles’ offensive game plan. Here’s a closer look at how they may do it:

Outside Speed Rush

Mack can get to quarterbacks in a variety of ways, each dangerous. He can turn the corner with an outside speed rush, he can slip inside with a counter move, and he can bull rush. Here he is using the speed rush, and his considerable bend, to get around Packers right tackle Jason Spriggs and sack Aaron Rodgers.

Eagles coach Doug Pederson: When he was drafted in Oakland, we thought, “This kid is a special kid.” We saw him twice a year. He got better each time we played him.

Johnson, with his quickness off the ball and his agility, usually eats speed rushers for lunch. In last year’s matchup, Mack was never able to successfully turn the corner on the tackle.

Pederson leaves his tackles on islands as much as any play caller.

Pederson: Obviously, the more guys you can get out on the route a little bit, [the] better.

But the Eagles do chip block with their tight ends and running backs and did a fair amount to keep Mack off balance last year.

Pederson: One on one, you’re not going to slow him down. It’s going to [force] you to do different things with tight ends, do different things with running backs. It can force you to change your thinking.

Here’s running back Corey Clement helping Johnson vs. a Mack outside speed rush last year.

Inside Counter Move

Mack has a plan each time he rushes. He often uses his speed rush to set up his inside move and will get tackles to overset. The inside move is particularly valuable if an offense has plans to chip or double Mack, as the 49ers likely did here.

Mack rushed almost exclusively from the left when he was with the Raiders. Now when he jumps to the other side, he’s almost as dangerous. He had 7-1/2 sacks and 30 hurries rushing from the left, and five sacks and 19 hurries coming from the left this season.

In this rush against the Rams, he not only got veteran left tackle Andrew Whitworth to overset, but he slipped inside the guard and strip-sacked Jared Goff. The 6-foot-3, 252-pound Mack has long 34-inch arms and he uses them to force fumbles even if he can’t wrap up quarterbacks. His six forced fumbles were tied for second in the NFL.

Mack will vary his stance, but when he’s in a three-point stance, that typically means that he’s coming. And when’s coming, there are few edge rushers as explosive. He took an inside path on this rush and lowered his head into the guard with so much force that he drove him on his heals.

Pederson: He’s a tremendous player, especially on third down when he can gear up and get after the quarterback.

Inside Stunts

Offenses will sometimes slide protection to Mack’s side, but that can create one-on-one matchups for above-average pass rushers like Floyd on the other side or defensive end Akiem Hicks inside. It can also backfire vs. stunts and twists.

In the Bears’ first game against the Vikings, Mack hit quarterback Kirk Cousins early after an outside rush. Minnesota didn’t slide protection here, but they did have a running back set to chip him. But Mack stunted inside and had a free path to Cousins.

Games up front take a little extra time to develop. The Eagles may have to favor the pass vs. the NFL’s No. 1-ranked run defense, but Pederson could lean heavily on the quick-pass game, which Foles has thrived in over the last three games.

Pederson: Sometimes the ball out fast can sort of nullify a rush, which you saw early in the Rams game.

Foles can’t hold the ball too long. Even if sliding protection toward Mack slows him, he has the motor to run down quarterbacks outside the pocket.

Bull Rush

We’ve seen Mack go outside and inside, but he can also go through tackles. On this rush against the Lions, he slipped the tight end and then ran over the tackle on the way to sacking Matt Stafford.

It was the second time Mack used a bull rush to take down Stafford, but this time he rushed standing up from the right.

Center Jason Kelce will help Foles and the rest of the line keep tabs on Mack.

Kelce: You need to be aware of where he’s at, but it doesn’t change up too much. He’s lining up at both places now, but we’re fortunate that we have two really good tackles.

If Johnson struggles, it’s often against stronger edge rushers. Johnson has a three-inch, 70-pound edge, but Mack drove him back here and drew a holding penalty.


Fangio doesn’t blitz much. But with an odd-man front, and stand-up edge rushers like Mack and Floyd, he’ll mix up his four-man rushes.

Eagles tight end Zach Ertz: He has those front seven guys doing a lot of stuff on defense. That’s always been the hallmark of his defenses is those front seven guys.

Mack dropped into coverage only 12 percent of the time, but he did it most against the Patriots and the Rams.

Tricking Mack Up

Most offenses rarely leave a tight end alone on Mack, but there are ways to frustrate him by using the tight end. Last year, the Eagles had success running away from Mack with just Ertz there to shield him.

Or they left him unblocked and used his aggressiveness against him, as they successfully did vs. the Broncos’ Von Miller earlier in the season.

Ertz: Any time a really good player gets taken away they’re going to be frustrated. They want to be making plays, especially in the playoffs. … I think it’s a sign of respect. We’re not going to let one guy kind of disrupt the entire game plan, and he’s a guy that definitely has the potential to do that.

The Giants tried to leave Mack unblock on this play earlier in the season, but he used his athleticism to break up the pass.

The Eagles once used a tight end [Brent Celek] and a running back [Jay Ajayi] to block Mack last season and it worked -- for the most part.

But going too much to that well could turn disastrous. On this play, the 49ers tried to wham block Mack to no avail.

Ertz: He’s a monster. He’s one of the top three players in the league on defense, probably top two. … There may be times I have to chip. At the same time, we have Lane Johnson, who is probably the best right tackle in the league. J.P. is probably a Hall of Famer.

Johnson was called twice for holding Mack last year, once on the above pass play and here on a run play.

But he more than held his own. Peters has yet to face Mack in his career. He’s faced and held off some of the best edge rushers over the last 15 years, but this will be a test at the age of 36.