Packers-49ers could turn on Christian McCaffrey vs. a vulnerable run defense

San Francisco 49ers All-Pro running back Christian McCaffrey was in the MVP conversation this season and has been a problem for the league all year.

On Saturday when the NFC's No. 1 seed hosts the upstart Packers (8 p.m. ET on FOX and the FOX Sports app), he likely will be a big problem for Green Bay defensive coordinator Joe Barry, whose unit allowed 128 rushing yards a game during the regular season, No. 28 in the NFL. 

The league leader in rushing yards (1,459) and scrimmage yards (2,023) during the regular season, McCaffrey has not played since suffering a mild calf strain on Dec. 31 against the Washington Commanders. He's now rested and has been a full participant in practice this week.

McCaffrey said it'll be business as usual for the 12-5 Niners come Saturday night. 

"I feel juice in this locker room every week," he told reporters. "Obviously, with the playoffs this matters. I think guys are obviously extremely anxious to get out there on the field and play. They're excited, but that's what is so cool about this team: Whether it's Week 4 or Week 10 or the divisional round, I love that this team is ready to go."  

San Francisco offensive line coach/run game coordinator Chris Foerster said McCaffrey's work ethic matches his talent, making him a game wrecker every time he steps on the field.

"He's in that group with the elite guys," Foerster said. "Like I've said in the past, working with a Peyton Manning or working with a Jonathan Ogden or Randall McDaniel — you work with these guys that are Hall of Fame type players, they prepare like nobody else does. 

"They're almost crazy about their preparation. They're never going to let up. They leave no stone unturned as far as game planning, their work or their preparation. And Christian's in that group of elite players." 

Niners coach Kyle Shanahan said McCaffrey is primed to get back to his ankle-breaking ways.

"He's geared up and ready to go," Shanahan told reporters this week. "Same way he was last year. Probably the same way he was in his playoff game when he was 5 years old, or a scrimmage that week.

"Christian is always the same. He's always waiting for that moment. He's been waiting for this moment for a while."

McCaffrey regularly created explosive plays for San Francisco's offense, leading the NFL with 38 runs of 10-plus yards. The 49ers finished No. 3 in the league in scoring, averaging 29 points a game.

"There's at least four guys over there that can get yards after contact," Packers head coach Matt LaFleur said about San Francisco's offense. "That's why I think it's so imperative that you have to swarm as a defense. You've got to have multiple bodies in position to make tackles. You truly have to gang tackle these guys." 

McCaffrey is San Francisco's go-to player in the red zone. He had 75 red-zone touches during the regular season, three times as many as No. 2 Deebo Samuel, and scored 18 touchdowns from inside the 20-yard line. Overall, McCaffrey finished tied for a league-high 21 touchdowns during the regular season, just two short of the franchise record held by Jerry Rice.

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The 49ers offense finished with a 51.8% success rate in the red zone during the regular season, tops in the NFL. Green Bay's defense allowed red-zone points 50.1% of the time, No. 9 in the league. In the Packers' victory over the Cowboys last week, Dallas was 4-of-5 (80%) in the red zone. 

Teams have tried to stack the box to try and stop McCaffrey. According to Next Gen Stats, he faced a light box on only 19.5% of his carries this season, the lowest rate in the NFL. But, obviously, he continues to have success.

And McCaffrey has been successful in the postseason, posting four games with at least 50 scrimmage yards and a touchdown.

Along with McCaffrey, the 49ers also have another key player back fully healthy in left tackle Trent Williams, who has been dealing with a lingering groin strain. That makes their running game work even better.

Per Next Gen Stats, the 49ers run to the left side nearly 60% of the time when Williams is on the field, averaging 5.7 yards per carry. 

On Saturday night, that's where the game could be won and lost.

Eric D. Williams has reported on the NFL for more than a decade, covering the Los Angeles Rams for Sports Illustrated, the Los Angeles Chargers for ESPN and the Seattle Seahawks for the Tacoma News Tribune. Follow him on Twitter at @eric_d_williams.