SANTA CLARA, Calif. -- Days before the San Francisco 49ers played the New York Giants in Week 9, rookie defensive linemen Mykel Williams and CJ West were in mid-conversation when the reality of how long and difficult the NFL season is dawned on them.
"I was like, 'Man, we still got a whole college football season left on the schedule,'" West said. "And it was like, 'Yeah, there's a lot of games left and it's a lot of room for improvement as well.'"
The marathon of this season is not lost on the Niners' 11-player rookie class, eight of whom are on the active roster. Through 10 games, there's no group that better embodies the ups and downs of this San Francisco season.
Every member of the Niners' rookie class has faced the harsh reality of playing for a team that expected them to contribute in Year 1 but still needs them to develop. A few days after his conversation with West, Williams' first season took a devastating turn.
Late in the 49ers' win against the Giants, Williams' tore the anterior cruciate ligament in his right knee, ending his season. The loss of Williams not only represented another hit to the 49ers' roster, but also meant he won't be getting valuable reps.
Although Williams, the No. 11 pick in the 2025 draft, had one sack, he'd proved an integral part of an improved run defense and generated pressure as an inside pass rusher in obvious throwing situations.
A few days before the injury, Williams laid out all the things he was learning in his rookie season, noting everything from the importance of red-light therapy for body recovery to resisting the urge to freelance no matter how tempting it might be to try to make big plays outside the structure of the defense.
"I'm just really disappointed that he is not able to really continue developing through this year because I believe we got a hell of a player who's going to really figure this out in the run game and the pass game," coach Kyle Shanahan said. "He still will, but I hurt for him that he isn't going to do that over the next half of this year."
The pressing questions for the remaining healthy members of the rookie class are how many opportunities they will have and how it goes as this season wears on. While few NFL players enjoy a linear progression, this year's draft class was thrust into bigger than expected roles right away because of injuries in front of them.
In a Week 5 win against the Los Angeles Rams, the 49ers had six rookies play at least 33 snaps, four of whom started. That included 89 from guard Connor Colby and 74 from safety Marques Sigle. Williams, defensive tackle Alfred Collins, nickel corner Upton Stout and West also were heavily involved.
Fast-forward more than a month to Sunday's loss to the Rams, and the Niners had only one rookie (West) play more than 33 snaps, with Stout the only other rookie serving as a meaningful contributor. Sigle and Colby were pregame scratches because previously injured teammates returned, and Collins also missed the game because of a hip injury.
In the first five weeks, 49ers rookies combined to play 1,294 snaps, ranking sixth in the league. Over the past five, that number has dipped to 878, which ranks 17th.
All of those snaps have value, according to defensive coordinator Robert Saleh, but it's also important for them to stay involved.
"They've got to be deliberate in everything they do," Saleh said. "They've got some game-time experience. Now it's working with the show team and making sure they're being deliberate with their techniques, their fundamentals, taking advantage of every rep and individual drills throughout practice, their one-on-ones, the reps that they do get in team, so they're not just on the bench. ... Their job is to be a pro, regardless of whether they're playing or not, and to continuously put themselves in position to be available and effective when their time comes up again."
A fifth-round pick out of Kansas State, Sigle might represent the most interesting case study of the group. The Niners didn't envision Sigle winning a starting job to begin the season, but with Malik Mustapha recovering from a knee injury, Ji'Ayir Brown working through an ankle issue and Talanoa Hufanga departing in free agency, Sigle impressed coaches with how quickly he learned in training camp.
Sigle started the first seven games, posting 45 tackles, a fumble recovery and two passes defensed. He played a huge part in the fourth-down stop on Rams running back Kyren Williams to ice the Niners' Week 5 victory.
Just four weeks later, Sigle has been a healthy scratch after Mustapha and Brown returned and reclaimed the starting safety jobs.
So far at least, Sigle is taking Saleh's words to heart and trying to use the experience he gained to reflect and improve so he can be better when he gets his next opportunity. Sigle points to a need to be better at finishing plays, noting how he often gave up completions despite being close in coverage.
"If I finished those plays, it's a whole different story," Sigle said. "My mindset is just to be violent in everything I do. I was in position, I've just got to be more violent, so I preached that, try to be attacking that in practice with my mindset and everything I do."
While many of the 49ers' rookies aren't as involved as they were early in the season, there's still reason to believe they'll be back in the mix. A hip injury kept Collins out last week, but he's expected to be back in the rotation soon. Stout has nailed down the nickel corner job, and Shanahan and Saleh have made it clear they're willing to live with the bumps along the way so he can gain experience.
West dealt with a thumb injury but played a lot against the Rams last week, while third-round linebacker Nick Martin is still attempting to contribute beyond special teams.
Given the number of injuries on defense, it's reasonable to expect the rookies to get plenty of more snaps over the season's final seven games. Niners rookies have played 1,438 defensive snaps this season, a 15.4% share that ranks second only behind the Atlanta Falcons, and their rookie defensive linemen have played a combined 740 snaps, easily the most by any team's group.
San Francisco's defensive rookies have combined for 124 tackles, two sacks, eight tackles for loss, a forced fumble, four fumble recoveries, four pass breakups and 21 pressures.
"A lot of times they're just playing off of pure physical ability," Saleh said. "There's a lot of things happening mentally that they're still unaware of. ... There are going to be mistakes. They are going to gain some scars, but as long as they're getting those scars at a hundred miles an hour, you trust that eventually they'll learn and maintain their speed while executing at a very high level."
Although the 49ers didn't invest as much in the offense during the draft, they have gotten significant contributions from Colby, who was thrust into the starting lineup after an injury to left guard Ben Bartch in Week 2. He started the next five games with mixed results. Receiver Jordan Watkins (fourth round) and running back Jordan James (fifth round) have both dealt with injuries in the preseason. Watkins has been active for only three games, and James hasn't been active in any.
Regardless of their roles, however, the rookie class has impressed the veterans with their willingness to ask questions.
"Our rookie class here is very eager to learn and none of 'em really have an ego," tight end George Kittle said. "They have their swagger to them, but they're all appreciative of the opportunity to be a 49er."
Niners rookies have also delivered in key moments. Stout's pass breakup in Week 3, Collins' forced and recovered fumble in Week 5 and Watkins' 19-yard catch to keep a drive moving in Week 10 are a few examples of the contributions the youngsters have made.
Considering how this season has gone from an injury standpoint, more opportunities are likely to come.
"From the beginning they needed us and each week a different rookie stepped up," Sigle said. "We are all going through the same experiences, whether that's playing every snap or playing a few or watching. We're just learning from each other's mistakes and each other's greatness and taking it day by day."