Run defense will decide whether 49ers can advance to NFC Championship

The 49ers have to fix this.

Darren Yamashita-Imagn Images

The San Francisco 49ers have been able to mask their weaknesses with smart gameplanning and timely performances all season. While that did not come in Week 18 against the Seattle Seahawks, the team gets a second chance at life in the Divisional Round this weekend. 

If the 49ers want to have any chance at advancing to the NFC Championship game, they are going to need the run defense to perform drastically better. 

San Francisco 49ers run defense is key to Divisional Round

Thomas Valentine of Pro Football Focus went through a matchup to watch for every game this weekend and highlighted the 49ers bad run defense against a weak Seahawks rushing attack as the matchup of the game. 

The 49ers will likely be without linebacker Fred Warner (93.2 grade; 1st) for one more week, with the All-Pro aiming for a potential NFC title game return — if the 49ers get there. However, they could desperately use Warner against the Seahawks' run game, especially considering how their Week 18 matchup played out.

The Seahawks’ run game has been inconsistent for most of the season, but it made an impact against the 49ers in Week 18. Kenneth Walker (88.4 grade; 2nd) and Zach Charbonnet (86.7 grade; 3rd) combined for 171 rushing yards and a touchdown on 33 carries. Walker and Charbonnet added six rushes of 10 yards or more, and three rushes of 15-plus yards. Those explosive plays ripped open an already wounded 49ers defense that has earned a 44.5 PFF run-defense grade in 2025, 31st in the NFL.

Thomas Valentine

It is true that the Seahawks rushing attack is their biggest weakness. They rank 8th in Expected Points Added and 4th in success rate when they throw the football. However, they rank 22nd in Expected Points Added and 23rd in Success Rate when it comes to their ground game. 

Their left tackle situation is up in the air, they have switch their starting center, and right guard is their weakest offensive line spot. This is where teams can beat them. 

The Los Angeles Rams have been able to force turnovers from Sam Darnold by shutting down the run in nickel looks and forcing him to throw from heavy personnel against their better coverage defenders. The 49ers need to find a way to do the same.

On the back end, it makes sense to keep Upton Stout on the field even if the Seahawks get into their heavier looks. However, it relies heavily on the front to win its matchups. 

The issue is that San Francisco is 17th in Expected Points Allowed and 31st in Success Rate. They avoid allowing big plays, but down-to-down, they get gashed. 

Sam Okuayinonu, Alfred Collins, Jordan Elliott, and Bryce Huff are likely the ones to get the most snaps this week. They are going to decide a significant portion of this game. 

If the Seahawks can establish a ground game, they can start to get passing lanes. Once they can pass, the entire group is far too tough to stop. If they cannot run the football, they start to get stagnant on offense. 

The 49ers have not been good at defending the run, but despite a long run to Saquon Barkley, they handled themselves down-to-down against him. It will be interesting to see if they can show up with a better performance than the last time these two teams met.