SANTA CLARA >> De’Vondre Campbell won’t be the last 49ers defender out that door before next season.

Just don’t expect an overhaul as jarring as this season’s.

So says defensive end Nick Bosa, who’s circling the wagons and throwing support behind his loyal teammates and first-year defensive coordinator Nick Sorensen.

Bosa insists the last-place 49ers (6-8) are hitting a stride that would be timed right for a playoff run, if only they hadn’t already fallen out of contention with three games left, including Sunday’s at the Miami Dolphins (6-8).

“A lot of people — you guys, in particular — are going to say, ‘Get these guys out of there, get these guys out of there. It didn’t work, it didn’t work,’ ” Bosa said Monday at his locker. “There’s going to be a lot of criticism next year when it looks very similar.

“That’s just what I feel, because we have the right people in terms of coaches and players. We have the right guys — defensively is what I can speak on.”

Campbell never looked quite right starting in place of Dre Greenlaw, up until Greenlaw’s season debut Thursday night forced Campbell to the bench where he refused to play from, even when called upon in the third quarter of a 12-6 loss to the Los Angeles Rams. Campbell is now suspended through the regular season as his one-year, $5 million contract expires.

Although the 49ers’ short-handed defense couldn’t halt the Rams’ fourth-quarter comeback, Bosa came away excited from what he saw on film, and not just because he emerged relatively healthy after a three-game hiatus (oblique, hip).

“Obviously it didn’t turn out this year (or) that game like we wanted, but I see a lot of guys in our D-line room and I want all of them back next year,” Bosa said. “We have all the players in our room right now to be that dominant line, and we looked like it Thursday night.”

Prisoner of the moment? The 49ers may have excelled on defense the past two games, Thursday’s rainstorm impacted Matthew Stafford’s aerial attack and the Niners’ seven sacks the previous game came against rookie Caleb Williams. Lopsided defeats to the Green Bay Packers (35-10) and the Buffalo Bills (38-10) showed how much the 49ers missed Bosa (and Greenlaw, Talanoa Hufanga and Javon Hargrave).

Get this: The 49ers are allowing the NFL’s third-fewest yards per game (298.8), behind only the Philadelphia Eagles (275.6) and Tennessee Titans (297.4).

Giving up points is more of a tell-tale sign about defenses – and overall complementary team football. The 49ers have the third-worst defense inside their 20-yard line, with opponents scoring touchdowns on 67.4% of their red zone drives. An average of 22.9 points per game are being scored on the 49ers, ranking middle of the NFL.

Key defenders unsigned for 2025: Greenlaw; cornerbacks Charvarius Ward and Isaac Yiadom; safeties Hufanga and Tashaun Gipson; defensive tackles Kevin Givens and Khalil Davis; and linebacker Demetrius Flannigan-Fowles. Two promising newcomers, defensive end Sam Okuayinonu and defensive tackle Evan Anderson, are exclusive rights free agents.

Overlooked amid the 49ers’ nonstop negative news this year has been the defense’s overhaul, starting with Sorensen’s promotion to replace the one-and-done Steve Wilks as coordinator.

Status quo is A-OK with Bosa: “I was thinking about it this weekend: People wanted Wilks out the door, and they wanted Sorensen out the door all year. Nick’s done a great job. You can’t play the play for the players. You can make calls and he’s gotten better.”

The defender who improved most this season was cornerback Deommodore Lenoir, and he was recently rewarded with a contract extension (five years, $89 million).

“This season, we had a lot of injuries, but it just fueled us for next year,” Lenoir said Monday. “We’re always going to try to come back and be better.”

Greenlaw’s comeback maxed out Thursday night after 30 snaps (and eight tackles). He did not practice Monday, so there is doubt how much the 49ers will push his rehabilitated left leg this final month.

Both Bosa and Lenoir staunchly advocated for the 49ers to re-sign Greenlaw, who is finishing out a team-friendly extension (two years, $16 million). His absence was glaring through 13 games, and not just because Campbell couldn’t aptly replace him or complement Fred Warner.

“I’m praying we re-sign him and get our dog back. He looked well worth it,” Lenoir said.

Bosa suggested skeptics look at the career-high sack totals being pursued by fellow linemen Leonard Floyd (8.5 sacks; two shy of his 2020 and ’23 top marks), Maliek Collins (five sacks; ties his 2016 and 2023 top marks) and Yetur Gross-Matos (four sacks; one away from surpassing last year’s best tally).

“I’m not saying we’ve been playing great defense all year because our red zone has been awful,” Bosa added. “We had to throw in a lot of young guys early on and that can cause confusion and breakdowns. But at this point, we’re hitting our stride, and that’s when we would be going on a playoff run. We just didn’t do enough to go on a playoff run.”

Roster moves >> Cornerback Ambry Thomas, who was the 49ers’ third-round pick in 2021, was waived from injured reserve. Thomas appeared in 42 games, including 11 starts, and had 65 tackles, 12 passes defensed and two interceptions returned for touchdowns.

In other moves, offensive tackle Austen Pleasants and linebacker Chandler Wooten were signed to the practice squad. Tight end Mason Pline, a practice squad member, was placed on injured reserve.