When the 49ers entered the 2025 NFL Draft, they did so with a clear mission: rebuild the defensive foundation. And they didn’t just dip their toes in - they dove in headfirst.
Six of their selections were defensive players, including their first five picks. The results?
A mixed bag, largely due to injuries, but with enough promising flashes to suggest the front office may have found a few long-term pieces.
Among the most encouraging developments was the emergence of rookie defensive tackles Alfred Collins and CJ West. As the season wore on, both players showed real growth, particularly in the trenches against the run.
Their presence helped stabilize a front that had been pushed around too often in recent years. And while neither was perfect, the arrow is definitely pointing up.
Then there’s Upton Stout, a cornerback who might’ve been the most impressive of the rookie class. His aggressive approach in run support stood out, and he added some eye-catching plays in coverage down the stretch. For a defense that’s looking to get younger and faster on the back end, Stout’s emergence was a welcome sight.
Marques Sigle also deserves a mention. After starting the first seven games, he lost his spot in the lineup, but his performance in the playoff win over the Eagles was a reminder of his potential. If he can build off that showing, he could carve out a bigger role moving forward.
But the biggest swing - and potentially the biggest payoff - came with the 11th overall pick: defensive end Mykel Williams.
Williams’ rookie season was cut short by a torn ACL in Week 9, and that injury clouds the full evaluation of his debut campaign. Still, before he went down, the former first-rounder was beginning to show exactly why the 49ers invested their highest pick since 2021 in him.
Drafted primarily for his ability to anchor the run defense, Williams also carried some pass-rushing upside that the team hopes to unlock over time. And while he finished the season with just one sack, the tape tells a more nuanced story.
In Week 1 against Seattle, Williams drew a triple team on the game’s decisive play, freeing up Nick Bosa to force a fumble. That’s not the kind of thing that shows up in the box score, but it’s the kind of unselfish, high-impact play that coaches love.
He also collapsed the pocket from the interior - where the Niners envision him long-term - to help set up another Bosa sack against the Saints. And in Week 3, he posted a season-high six pressures against Arizona.
The flashes were real, even if the sack numbers weren’t.
But where Williams really made his mark was against the run - and the numbers back that up in a big way.
With Williams on the field from Weeks 1-9, the 49ers ranked sixth in the league in EPA per play against the run. After his injury?
That number plummeted to 26th. That’s not a coincidence.
Williams consistently set the edge, held his ground against tackles, and flat-out dominated tight ends in the run game. He only had four tackles for loss, but a deeper dive into the metrics tells the full story.
His average depth of tackle against the run was minus 0.1 yards - the best mark of any edge defender with at least 100 run defense snaps, per Pro Football Focus. That means he was meeting runners at or behind the line of scrimmage more often than anyone else in his rookie class.
His run stop rate (6.2%) ranked third among rookie edge defenders with 100+ snaps. In short, Williams wasn’t just holding his own - he was winning.
And that mattered. Because once he was out of the lineup, the 49ers’ run defense lost its edge - literally and figuratively.
Too often, they got pushed around up front, something that had been a recurring issue in recent years. Williams, even in a limited sample, looked like the antidote to that problem.
Now, the focus shifts to his recovery. A torn ACL is no small hurdle, especially for a player whose game is built on explosiveness and leverage. But if Williams can return to form - or better yet, take that year-two leap - the 49ers may have found a key building block for a defense that needs more physicality in the trenches.
With plenty of personnel decisions looming this offseason, one thing is clear: getting Mykel Williams back to full strength might be one of the most important developments for San Francisco’s 2026 outlook. If he’s healthy, the Niners have a shot to flip the script - and become the bullies in the trenches once again.