What to expect from the Chargers, how the Patriots match up, and why RBs will be key

Bill Belichick isn’t messing around this week. The Chargers are coming to town for a playoff matchup with the Patriots, and they have Belichick’s full attention.

“This is a very good football team,” Belichick said Monday. “Extremely talented. They can run it. They can throw it deep. They can throw it short. They can make explosive runs for 50 yards and they can grind it out with good, tough, hard-nosed runs for tough yardage that they need. It’s a very well-coached, well-balanced, disciplined football team.”

The Patriots and Chargers have played just twice in the last five seasons, and Belichick has faced Chargers coach Anthony Lynn only once in Lynn’s two seasons. But there is some familiarity between the teams.

The Patriots have faced quarterback Philip Rivers eight times in his 13 years as a starter, compiling a 7-1 record (his only win came over Matt Cassel in 2008). They are familiar with defensive coordinator Gus Bradley, who runs the same Seattle Cover 3 scheme that the Patriots faced against the Seahawks and Falcons in Super Bowls.

And last year’s Patriots-Chargers game in Week 8, a 21-13 Patriots victory, has a lot of carryover. The coaches and schemes are the same, and so are many of the players. The NFL usually changes significantly from year to year, but this is as close to a rematch as you will get.

To get a better feel for the Chargers, we watched the All-22 tape from their final two regular-season games, a 22-10 loss to the Ravens and a 23-9 win over the Broncos, plus selected plays from the second half of the season.

Here is what to expect, and how the Patriots match up:

Offense

Coordinator: Ken Whisenhunt (third season).

Rankings: Sixth in points (26.8 per game), 11th in yards (372.6 per game).

Key personnel: QB Philip Rivers, RB Melvin Gordon, RB Austin Ekeler, WR Keenan Allen, WR Mike Williams, WR Tyrell Williams, TE Antonio Gates.

Injuries/lineup notes: TE Hunter Henry was activated off injured reserve Monday after missing the entire season with a torn ACL, and his role Sunday is unclear. Gordon is dealing with a left knee injury but is likely to play.

What to expect: Belichick wasn’t hyperbolizing about the Chargers offense. They weren’t elite in any one area but they were good across the board.

The Chargers ranked 10th in passing offense and seventh in rushing average (4.7 yards per carry). They allowed the 10th-fewest sacks (34). And they can push the ball downfield, as Rivers tied for sixth in passes of 25 yards or more.

We wrote Monday about the Chargers’ imposing size on offense: big receivers, big tight ends, a big offensive line. But this game should be all about the running backs, as both the Chargers and Patriots rely heavily on their backs in the passing game.

The Chargers’ 1,050 receiving yards by running backs were the most in the NFL, and the Patriots’ 999 were second. The Patriots led the NFL with 172 pass attempts to running backs, and the Chargers were sixth with 141.

James White is the workhorse in New England, but the Chargers have a two-headed monster. Gordon had 50 catches for 490 yards and 4 touchdowns; Ekeler had 39 catches for 404 yards and 3 touchdowns.

Stopping Gordon and Ekeler should be the Patriots’ primary goal. Gordon rushed for 885 yards, 10 touchdowns, and averaged 5.1 yards per carry. The Patriots are well aware of his breakaway speed after allowing an 87-yard touchdown to him last year and 132 rushing yards overall. This year, Gordon took a simple swing pass against the Raiders and took it 66 yards to the house.

He is a physical, 215-pound runner who is tough to bring down.

Ekeler rushed for 554 yards, 3 touchdowns, and averaged 5.2 yards. He gained 41 percent of his yards after contact. The Patriots’ run defense, allowing 4.9 yards per carry (29th), will have a tough test against a big, physical offensive line.

The Patriots are often happy to let the opposing running backs cut it loose, because it means taking the ball out of the quarterback’s hands. But not with the Chargers — stop the running backs first, and make them beat you on the outside.

That’s not a guaranteed formula for success, though, because the Chargers have a quarterback who can win from the pocket. Rivers, 37, had one of the best seasons of his career. His 68.3 completion percentage was his best in six seasons. His 8.5 yards per attempt were his best in nine seasons. He threw for 4,308 yards, 32 touchdowns, and 12 interceptions, and should be a top candidate for MVP.

Rivers may be the only NFL quarterback less mobile than Tom Brady, but he shuffles around the pocket well, stands tough in the face of the pass rush, and knows when to bail on a play.

Whisenhunt gives Rivers a lot of freedom at the line of scrimmage to get the Chargers into the right play. You often see Rivers barking instructions at teammates as the play clock winds down, and unfortunately for the Chargers, this resulted in six delay-of-game penalties this year, tied for most in the league.

Rivers doesn’t put much zip on the football, and the Broncos did a good job two weeks ago of disguising their blitz, baiting Rivers into bad decisions and undercutting the routes for two interceptions.

Rivers also has a tendency to throw off his back foot in the face of the blitz, which led to two wobbly duck interceptions against the Chiefs last month.

Bad things can happen when Rivers is blitzed; he threw four interceptions against the blitz this year. Expect the Patriots to continue using their “amoeba” package to disguise their rush and bring plenty of heat.

But Rivers is also deadly accurate. He throws an excellent back-shoulder pass to his two big receivers on the outside, Mike Williams and Tyrell Williams.

Both receivers are 6 feet 4 inches, and Rivers throws a good corner fade in the end zone.

Their size will be a challenge for the Patriots cornerbacks, who aren’t that big, other than Stephon Gilmore. Rivers also made arguably the throw of the year last month against the Chiefs, threading one perfectly to Travis Benjamin for 26 yards on fourth and 7.

The Chargers run pretty much the entire route tree: short and deep crossers, sideline fades, back-shoulder throws, double moves, quick hitches, and swing passes out of the backfield. They don’t have a lot of speed, but Benjamin is a threat on end-arounds and deep balls, similar to Cordarrelle Patterson. Allen is a tremendous possession receiver, catching 97 passes for 1,196 yards, but he was just 50th among wide receivers in yards after catch.

The Patriots can’t afford to let Rivers sit comfortably in the pocket. They need to blitz him into oblivion, especially up the middle, to force him into bad decisions.

Defense

Coordinator: Gus Bradley (second season).

Rankings: Eighth in points allowed (20.6 per game), ninth in yards (333.7 yards per game).

Key personnel: DE Joey Bosa, DE Melvin Ingram, DT Darius Philon, LB Uchenna Nwosu, DB Desmond King, CB Casey Hayward, S Derwin James, S Jahleel Addae.

Injury/lineup notes: LB Jatavis Brown, their third-leading tackler, went on injured reserve this week. The Chargers replaced him not with a linebacker but by playing extra defensive backs. In Week 14 against the Chiefs, the Chargers played six DBs the entire game. Last week against the Ravens, they played seven DBs the entire game.

What to expect: The Patriots know this scheme well. The Seahawks popularized it earlier this decade, and the Patriots have faced it in recent years against the Falcons, Jaguars, Chargers, and other teams. It centers around a single high safety playing about 20 yards off the ball — the Earl Thomas role, which is played by Addae in Los Angeles — and big, physical cornerbacks who generally play press man coverage, or drop back into a Cover 3 zone.

Like the offense, the Chargers defense isn’t dominant in any one area but is good across the board. The Chargers were ninth against the pass and ninth against the run.

Bradley has brought a few wrinkles to the scheme. The Chargers will mix in some two-high-safety, especially on passing downs. They do a lot of pre- and post-snap rotations to disguise their pass rush and their coverage. And they have taken their linebackers off the field in recent weeks in favor of extra defensive backs.

Remember how I said this game should revolve around the running backs? Not only are the Patriots and Chargers among the league leaders in throwing the ball to running backs, they also rank near the bottom in defending running backs in the passing game.

The Chargers allowed 973 receiving yards to running backs, second-most in the NFL, and 107 receptions, fourth-most. The Patriots allowed 783 yards (ninth) and 90 receptions (12th).

The Chargers allowed six running backs to gain at least 50 yards receiving, tied for third-most. They also allowed six receptions of 25 or more yards to running backs.

In last year’s meeting, the Patriots’ top two receivers were Rex Burkhead (7 catches for 68 yards) and James White (5 for 85).

Expect a heavy day for them again, because the Patriots don’t match up well with the Chargers in other areas of the passing game. The Chargers pass rush didn’t put up eye-popping numbers this year — their 38 sacks were tied for 19th — but Bosa, Ingram & Co. can wreck a game in a hurry.

Bosa likes to line up over the right tackle, but the two players move up and down the line. Ingram does a lot of pre-snap movement, and can beat a tackle around the edge or power through a guard.

The Patriots neutralized Bosa and Ingram last year, allowing just one sack and six tackles combined, as Brady got the ball out quickly and grinded his way to 333 passing yards on 47 attempts. But the Patriots offense was operating at a higher level last year, and Brady will have a tougher challenge this time.

Getting the ball out quickly to the wide receivers won’t be easy. The Chargers have good size at cornerback, including two All-Pros in King and James, who often comes down into the box.

The Cover 3 defense allows for big gains down the seams and on deep crossers.

But if the Chargers are smart, they will play a lot of press coverage to take away Chris Hogan or Phillip Dorsett (unlike the Jaguars, who played off coverage throughout last year’s AFC Championship game and allowed Brandin Cooks to chew them up).

Rob Gronkowski is also going to have his hands full with James.

Instead, Brady will need Julian Edelman to get open quickly underneath. And expect a bevy of screen passes and dumpoffs to running backs. Patterson also will be an important weapon on jet sweeps and quick screens.

The Patriots couldn’t get much going on the ground last year, rushing 32 times for just 97 yards (3.0). But if the Chargers continue to play six and seven defensive backs, Sony Michel could have some success, especially if the Patriots counter with their big personnel (Dwayne Allen and James Develin).

The Chargers do appear to have some softness up the middle of their defense. Broncos running back Phillip Lindsay had a 41-yard touchdown right up the middle, and Ravens running back Gus Edwards went for 46 yards up the middle.

The Chargers don’t blitz a ton but allowed the second-lowest passer rating with the blitz this season (63.8), with two touchdowns, three interceptions, and just one pass more than 25 yards. I expect them to play it safe against Brady — dropping seven or eight into coverage, hoping Bosa and Ingram can generate pressure, and making the Patriots grind out long drives.

This will be a big test for the Patriots offense, which is still figuring out its identity after losing Josh Gordon. They will need White, Burkhead, and Patterson to carry the day.

Ben Volin can be reached at ben.volin@globe.com. Follow him on Twitter @BenVolin