49ers Have a New Defensive Concern After Week 1

For the past few seasons, it has felt as though the San Francisco 49ers have had a good run defense, but they have not been able to find a consistent pass rush from their defensive line. Entering 2026, it looks like the team did a solid job addressing the pass rush from the interior. However, now it looks like the run defense could become a problem.

San Francisco 49ers' interior run defense is a problem

The team lost Alfred Collins days before the start of the season, which made it hard to replace. Collins was the best run defender on the team last year, and the 49ers signed Osa Odighizuwa and drafted Gracen Halton, assuming they would play beside Collins.

The two are a bit smaller, faster, and better as pass rushers. They fit next to Collins, and both flashed in Week 1. Odighizuwa had a ridiculous five pressures against the Rams, and Halton added a pressure of his own.

However, the plan was for these two to add pressure and for Collins to defend the run. C.J. West has the same role as Collins, but he showed less as a rookie and is expected to serve a smaller role.

He looked like an issue stepping into a bigger role. According to PFF, he had a 33.2 grade, which is very poor. He is supposed to be their best run defender and had the second-worst run defense grade of any player on the 49ers defense.

The 49ers defense shut down the Rams, but it was not because of the run defense. Rams running backs had 26 rushes for 114 yards, which led to 4.4 yards per attempt.

Kyren Williams had a 54.5% success rate. Blake Corum had a 70% success rate. Even Ronnie Rivers had a 60% success rate on his five carries. The only reason the Rams did not run the football more is that they trailed in the second half and had to pass the ball more.

If they had leaned on the rushing attack more in the first half, the game might have been closer in the second half.

Miami does not bring much that scares teams, but they do have Malik Willis and De’Von Achane. They both represent serious rushing threats.

The 49ers' run defense will be tested more in the coming weeks than it was in Week 1. Can they show they are ready?

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