2 keys to Sunday's wild-card games

Here's one key question for each of Sunday's playoff matchups.

Los Angeles Chargers at Baltimore Ravens

Can the Chargers slow the Ravens' running attack?

This may be the best game of the weekend, and it's a rematch of Week 16 when the Ravens pulled off a 22-10 upset on the road. Baltimore ran the football 35 times for 159 yards in that game, which nearly matched quarterback Lamar Jackson's 204 passing yards.

Overall, Baltimore's won six of seven since switching to Jackson - claiming the AFC North title in the process - while tweaking its offense to fit the rookie's natural talents. The Ravens are using more zone running designs that give Jackson the option to read a defender and either hand off the football or keep it himself.

However, aside from a 27-yarder, the Chargers' defense contained Jackson on the ground in Week 16, holding him to 3 yards or fewer on nine of his rushing attempts and 39 overall on 13 attempts. Los Angeles did so thanks to a defensive scheme known as the "scrape exchange," which its defense would be wise to implement once again on Sunday against the zone-read running plays from Jackson and Co.

On that type of play, the offense leaves one defender unblocked, typically the defensive end, who's referred to as the "read defender." Ideally, the flow of the play will serve as a natural block on that player. That's because upon taking the snap, the quarterback will put the ball in the belly of their running back and gauge the read defender's reaction - if he stays outside, the quarterback hands the football off to the running back aiming inside. If the defender crashes inside toward the potential handoff route, the quarterback keeps the football and scampers outside:

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This is where the scrape exchange comes in, which makes the quarterback's decision for them. This adjustment tasks the read defender with crashing inside no matter what, while having a linebacker "scrape" to the edge behind them. In essence, the defensive end and the linebacker exchange their gap responsibilities:

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This forces the quarterback's hand. When they see the read defender crash inside, they'll instinctively pull the football down and run to the edge, where - hopefully for the defense - the linebacker's now waiting.

Los Angeles did this to Baltimore in Week 16, at times using safety Adrian Phillips (No. 31) as the scraping linebacker:

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On this play, defensive end Isaac Rochell (No. 98) crashes down inside, which cues Jackson to keep the football. But Phillips loops around on the scrape, cutting Jackson down for a loss.

Slowing down Baltimore's zone-read running attack is a must for the Chargers if they hope to pull off a win on the road. The scrape exchange may just be the means of achieving that goal.

Philadelphia Eagles at Chicago Bears

Can Chicago force Foles to make critical mistakes?

For the second straight year, the Eagles are heading into the playoffs on the right arm of backup quarterback Nick Foles. After Carson Wentz went down in Week 15, the Eagles won three straight games, narrowly earning the NFC's final playoff spot as Foles racked up 962 yards and six touchdowns with a sparkling 77 percent completion rate.

Along with making quick decisions in the pocket, an element that's allowed Foles to thrive is his downfield execution. Compared to Wentz, his overall numbers are much better on longer attempts through the air:

Throws of 20-plus yards

QB	Completions-Attempts	Yards	TDs	INTs	QB Rating
Wentz	15 of 41	603	2	4	61.33
Foles	6 of 18	259	1	0	100.46

However, Foles did make some mistakes this season, and if the Bears can force a turnover or two on Sunday - a key to their success this year - the offense and second-year pivot Mitchell Trubisky should get opportunities to capitalize on short-field situations.

Chicago can do this by mixing up its coverages, which is something the Houston Texans did in their Week 16 matchup with Philadelphia. Early in that game, Foles hit running back Darren Sproles on a route out of the backfield for a long catch-and-run touchdown. The Texans used man coverage in the secondary on that play, which at least set up an unexpected look later in the game.

Below, facing a first-and-10, the Eagles line up with Sproles to Foles' right in the backfield. Alshon Jeffery is the single receiver to the right, while the Eagles have three receivers to the left, including tight end Zach Ertz, who's on the inside. Here's the route design, which includes mirrored slant/flat combination on both sides and Ertz running a "sit" route over the middle:

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Upon taking the snap, Foles initially looks right to work the slant/flat combination involving Jeffery and Sproles. Having seen man coverage earlier, Foles anticipates the linebacker will try to cover Sproles out of the backfield, which would create a natural rub given Jeffery's slant route. However, the Texans are actually running zone coverage, so the cornerback passes off the slant route to the linebacker and jumps the running back's route:

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This flusters Foles. He sees the cornerback jumping the flat route and pulls down the football, but then makes a panicked decision under pressure, forcing a throw to Ertz on the sit route, which is intercepted:

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The Bears - led by Khalil Mack - have been great at generating pressure on opposing passers this season. If they can effectively combine that pressure with some different looks in the secondary, they should be able to rattle Foles and create a turnover or two, which would put them on the path to victory.

Mark Schofield writes NFL feature content for theScore. After nearly a decade of practicing law in the Washington, D.C., area Mark changed careers and started writing about football. Drawing upon more than a decade of playing quarterback, including at the collegiate level, Mark focuses his work on quarterback evaluation and offensive scheme analysis. He lives in Maryland with his wife and two children. Find him on Twitter @MarkSchofield.

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