Jeff McLane’s keys to Eagles vs. 49ers in the wild-card round: What you need to know and a prediction

The Eagles host the San Francisco 49ers in a wild-card playoff matchup at 4:30 p.m. Sunday at Lincoln Financial Field. Here’s what you need to know about the game:

The 49ers don’t have a good defense. Season-ending injuries to their two best players — linebacker Fred Warner and defensive end Nick Bosa — were a prominent reason why coordinator Robert Saleh’s unit struggled most of the season. But there also isn’t much talent elsewhere on that side of the ball. The 49ers ranked 25th in expected points added per play and 29th in success rate. Saleh has been forced to play a bend-but-try-not-to-break defense, which has meant more two-high safety shells than he’s accustomed to employing and hoping that opposing offenses eventually will make mistakes on grind-it-out drives. The 49ers have done a good job of limiting explosive plays as a result and rank ninth in allowing 20-plus-yard plays in EPA. They’ve also buckled down in the red zone, where they rank 12th overall and fourth in goal-to-go situations.

The Eagles’ offense, conversely, has been at its best inside the 20 and ranked first in the league. Getting there on a consistent basis has been a season-long problem. The chess match here could center on which unit is willing to get out of its comfort zone. Will the 49ers play more aggressively and stack the box — only the Eagles and New England Patriots had a higher rate of light boxes — knowing the Eagles have struggled in the run game when numbers haven’t been in their favor? Or will the Eagles come out firing, looking for explosives through the air, knowing that Saleh likely will make Jalen Hurts and the pass game beat his defense?

Nick Sirianni and Kevin Patullo have several directions they can go that should favor the Eagles, even if the 49ers match heavy personnel with their base front. It would be foolish not to test San Fran’s run defense, especially an off-ball linebacker unit that could be down to its fourth and fifth options on the depth chart. Warner’s replacement, Tatum Bethune, went down for the season last week, which means the aging Eric Kendricks, the younger brother of former Eagle Mychal Kendricks, will be at middle linebacker. Outside linebackers Dee Winters and Luke Gifford also are questionable. The Eagles offensive line, with right tackle Lane Johnson expected to return, likely will need to adapt to a slanting front if they want to carry out their combo zone blocking schemes. But if even all doesn’t go according to plan, Saquon Barkley should have opportunities to do it on his own against a run defense that missed 11 tackles against the Seattle Seahawks in Week 18.

» READ MORE: Eagles vs. 49ers predictions: Our writers pick a winner for the wild-card round

I think more of Hurts on designed runs, and a sprinkling in of the more north-to-south Tank Bigsby, could further buoy a run offense that has shown marginal improvement over the last month. I wouldn’t be surprised to see Patullo open with a fair amount of empty sets. Hurts has operated well out of that formation. It forces defenses to have to account for his legs on draws or scrambles if they’re going to match in man coverage.

Saleh still favors Cover 3 more than any zone, but he’s going to have to pick his poison with Eagles receivers A.J. Brown and DeVonta Smith having skill and size edges over cornerbacks Deommodore Lenoir, Renardo Green, and Upton Stout. Logic would suggest that tight end Dallas Goedert should get a healthy dose of pass plays as the first read with the 49ers’ linebacker corps battered. The same could be said for getting Barkley more involved in the pass game. Hurts should have time in the pocket. San Fran’s pass rush has been deficient without Bosa. Former Eagle Bryce Huff may be the 49ers’ best edge rusher. I watched enough of Johnson and Jordan Mailata dominating him in training camp a year ago to think they’ll keep him under wraps on Sunday. The Eagles’ offensive line must be prepared, though, for a high rate of stunts that Saleh calls to offset his rushers’ inability to win one-on-one.

This is where the more intriguing matchup lies with 49ers coach Kyle Shanahan and Eagles defensive coordinator Vic Fangio, two of the best play-callers in the business. While Fangio’s defense has jelled into a unit comparable to last year’s, Shanahan’s offense hasn’t been as explosive as it was in previous seasons when the 49ers reached the playoffs. He still has one of the more sophisticated run schemes in the NFL, but the production just hasn’t been there for various reasons. Like the Eagles, San Fran has faced a high rate of stacked boxes. That often is by design. No team utilizes two-back personnel more than the 49ers, who have fullback Kyle Juszczyk. At 34, he isn’t as dynamic, but Shanahan lines him up all over, increasingly in an unorthodox offset position in which he can be a blocker in a variety of ways.

Christian McCaffrey remains the workhorse running back, often from under center. He finished second in the league in carries (311), but had the lowest rushing yards over expected per attempt (-0.5) of his career. The 49ers’ scheme has long majored in wide zone runs, but McCaffrey has had more success running in between the tackles this season. Shanahan’s offense often needs to establish its ground game to utilize play action. His two-back personnel will force Fangio to decide between using his base five-man front to stop the run or his preferred nickel four-man front to protect the back. It will likely be based on the situation, but Fangio doesn’t want to leave his secondary susceptible to throws off play-action. The 49ers’ run game had two strong showings vs. the Indianapolis Colts and Chicago Bears, but it regressed last week against an athletic Seahawks defense.

» READ MORE: Saquon Barkley is extra excited for a showdown with Christian McCaffrey, ‘one of the best to ever do it’

The possible return of Hall of Fame-bound left tackle Trent Williams (listed as questionable) would help San Fran, but if the Eagles contain McCaffrey, it could be a long day for Shanahan’s unit. He’ll scheme up pre-snap motions to manipulate a defense, and he’ll dial up naked bootlegs and screens to compensate for struggles on the ground. But his offense has been lacking in the dropback game without a top receiver who can consistently get separation downfield for quarterback Brock Purdy. Ricky Pearsall would be the best candidate, but he’s questionable after not practicing all week. That has left most of the heavy lifting to tight end George Kittle and McCaffrey, who led the team with 102 catches. Kittle can do it all. Shanahan will use him like a chess piece. He can win vs. linebackers, safeties, and cornerbacks. The Eagles’ Zack Baun, Reed Blankenship, and Cooper DeJean will be most responsible for keeping him in check.

Purdy isn’t just some byproduct of Shanahan’s genius. He’s quick through his progressions, has good pocket movements, and can extend plays as well as most quarterbacks. He’s not necessarily a scrambler, but he can run to the sticks. If you can collapse the pocket, the throws get harder for him because he’s only 6-foot-1. Purdy’s excellent when “hot,” so it makes little sense to blitz him much — not that Fangio would be inclined to send extra rushers a lot. Shanahan likely will go after cornerback Adoree’ Jackson with Quinyon Mitchell on the opposite side. Fangio has found ways to cover for Jackson with split-field zones. I also could see Purdy targeting safety Marcus Epps or returning linebacker Nakobe Dean on middle-field throws.

The 49ers have a lot of success throwing over the middle. But there’s a risk. Eight of Purdy’s 10 interceptions have come between the numbers. That’s part of the reason Hurts doesn’t throw over the middle as often as other quarterbacks. Sirianni has hammered winning the turnover battle into his team. The Eagles finished the season plus-6 in turnover differential, while the 49ers finished minus-6. I also give Sirianni the nod in game management and fourth-down decision-making. He has been more conservative this season, partly because the Tush Push is no longer close to automatic.

» READ MORE: Eagles’ postseason adjustments, concerns with the offense, breakout players, and other AMA highlights

Shanahan has lacked the gumption in key spots over his career. He’s a master game-planner and play-caller. But if his teams get behind, they often struggle to rally because his offense isn’t as strong in the dropback world. The same could be said for Sirianni’s system, as well. I think the first team to 20 points wins this game. The Eagles of old could salt away a second-half lead, but Sirianni and Patullo have been unable to find a formula when ahead. It’s been ugly at times and that should be worrisome. But this is how I see the matchup: There’s a push when it comes to the Eagles’ underperforming offense vs. the 49ers’ subpar defense; but I give the edge to a great Eagles defense over a very good, but not great 49ers offense.

Prediction: Eagles, 23-17.