49ers-Chargers joint practice roundup: The secondary had a rough outing

SEATTLE, WASHINGTON - JANUARY 17: Deommodore Lenoir #2 of the San Francisco 49ers enters the field with teammates prior to an NFL divisional playoff football game against the Seattle Seahawks at Lumen Field on January 17, 2026 in Seattle, Washington. (Photo by Brooke Sutton/Getty Images) | Getty Images

The San Francisco 49ers and Los Angeles Chargers held a joint practice on Tuesday. Kyle Shanahan provided the injury updates. Let's get right into the action.

Defensive struggles for the 49ers' secondary

It does not sound like the defensive backs enjoyed the success during the joint practice:

The #49ers DBs are not having a great start to the joint practice. They are getting toasted left and right. Chargers quarterbacks are finding the soft spots in the coverage for huge plays.

- Jennifer Lee Chan -all platforms: @jenniferleechan (@jenniferleechan) August 18, 2026

Justin Herbert and his receivers putting on a show against 49ers defense. Big step up in competition, scheme from the practice against Cam Ward and Titans last week.

- Vic Tafur (@VicTafur) August 18, 2026

A Chargers account is tweeting multiple clips. Like we did last week with the Titans, we'll use the opponents' perspective.

On this play, defensive tackle Alfred Collins makes a tackle for loss:

Hamp pic.twitter.com/aWMj8IVIWe

- Jason Delgado (@JasonDelgado78) August 18, 2026

On this play, Jaden Dugger gets blocked to the ground. However, his job is to ensure the running back doesn't get outside of him. That doesn't happen, which allows Dre Greenlaw to scrape through the trash and make a tackle near the line of scrimmage:

Mitchell torched the Niners! pic.twitter.com/wvda657EGv

- Jason Delgado (@JasonDelgado78) August 18, 2026

Here's Deommodore Lenoir allowing an easy reception for a first down:

QJ. pic.twitter.com/AkFhlQYSpB

- Jason Delgado (@JasonDelgado78) August 18, 2026

You can't see the result, but based on the reaction, Lenoir got mossed" and allowed a touchdown:

QJ TD! pic.twitter.com/FQcfFXnx9n

- Jason Delgado (@JasonDelgado78) August 18, 2026

Osa Odighizuwa would've annihilated Justin Herbert on this play, so the long touchdown would've never happened. Sounds like Odighizuwa had himself a day:

One defensive standout was Osa Odighizuwa. Half dozen sacks if they were allowing those kinds of things. #49ers

- Vic Tafur (@VicTafur) August 18, 2026

Romello Height had a sack. This touchdown never happens in a real game:

Niners secondary getting worked in joint practice

Via: @JasonDelgado78pic.twitter.com/YfwHsSGyf6

- OurSF49ers (@OurSf49ers) August 18, 2026

It's still not a great sign seeing Lenoir getting beaten deep and Ji'Ayir Brown being late to see a deep post route when that was his only vertical threat:

Herb deep and to Flash pic.twitter.com/IRD6L68wvz

- Jason Delgado (@JasonDelgado78) August 18, 2026

That's rookie wide receiver Brennan Thompson, who ran a 4.26 40-yard dash.

This play is a mess:

Njoku TD pic.twitter.com/v88FwkVQTe

- Jason Delgado (@JasonDelgado78) August 18, 2026

Marques Sigle is the deep safety. He takes himself out of the post (middle of the field) for a route that's being defended, despite a deep crossing route coming his way. Lenoir, who was guarding David Njouku, falls off the route and picks up a crosser from the other side, who Renardo Green is guarding. Two players are wrong, and that's how you get a coverage bust.

Here's more miscommunication. Either safety Ji'Ayir Brown is late and needs to recognize the running back sooner, or Green must fall off his receiver and pick up the back:

Herb finds Ingold pic.twitter.com/OnXZGicH1U

- Jason Delgado (@JasonDelgado78) August 18, 2026

More often than not, in these quarters coverages, the cornerback is going to defend the No. 1 wide receiver 1-on-1, provided he doesn't run a route under five yards.

You'd like to see Sigle get over to the tight end quicker and either break the pass up or intercept it:

Justin Herbert is DEALING HOLY SHIT 10+ TDs already vs 49ers defense at joint practice

Don't want to jinx it but 0 chargers turnovers, 49ers offense is struggling....

(Mike McDaniel we see you ) pic.twitter.com/5Fwr6m9QMi

- NFLMike (@TheNFLMike) August 18, 2026

If the 49ers are going to have a chance this season, Sigle is going to have to process what's happening faster than that.

I'm more interested in the personnel groupings than the result of this play. For example, on this red zone play, Jack Jones is in at corner instead of Renardo Green (who left after friendly fire with Fred Warner) and Larry Worth III is the third linebacker:

Herb to Ladd TD pic.twitter.com/VvuOzVsFCk

- Jason Delgado (@JasonDelgado78) August 18, 2026

Worth had a beat on the throw, but he lacked the spatial awareness of where he was in relation to the wideout. That should have been an interception.

That would not be the only touchdown Jones surrendered:

Herb to Ladd TD & celebration pic.twitter.com/kPugdyjXoC

- Jason Delgado (@JasonDelgado78) August 18, 2026

Speaking of safeties, here is Brown getting run over by Omarion Hampton:

Hampton trucking Niners! pic.twitter.com/Fly9d4BK9A

- Jason Delgado (@JasonDelgado78) August 18, 2026

If you leave your feet to tackle, bad things are going to happen.

It wouldn't be a practice without Fred Warner punching a ball out:

Njoku fumble pic.twitter.com/EGhcrkbXoV

- Jason Delgado (@JasonDelgado78) August 18, 2026

What an incredible skill that is.

Offense

Kaelon Black was reportedly active early on, as the 49ers are wasting no time throwing him into the mix:

Kaelon Black with a couple of big runs early. He doesn't look like someone who's missed the last couple of weeks.

- Matt Barrows (@mattbarrows) August 18, 2026

Kaelon Black is running with a purpose this morning. Broke a couple of big runs. Brock Purdy also looking really comfortable. Lots of rhythm throws. Good timing.

- Noah Furtado (@_noahfurtado) August 18, 2026

Black is no stranger to big runs either. He finished fourth in the country last season in the percentage of plays that resulted in an EPA of greater than +1.0 - an indication of highly successful, explosive plays for the offense.

As we know, that was a struggle for the 49ers' offense last season. The offense finished 21st in 10+ yard runs.

Barrows tweeted a clip of one of Black's gains, and it was probably a 3-yarder:

This was Kaelon Black's longest run of the day. Denzel Perryman (6) might have gotten him after a short gain. Black, however, seemed to think he would have broken the tackle. pic.twitter.com/VZCFVC7Jtk

- Matt Barrows (@mattbarrows) August 18, 2026

Here is one of those layer king" throws from Brock Purdy:

Defense! pic.twitter.com/shByAyLZvl

- Jason Delgado (@JasonDelgado78) August 18, 2026

The bigger takeaway is that Carver Willis is getting a shot at left guard, while Robert Jones is playing right guard with Dominick Puni (concussion) out.

Blocks like these are why Jones may no longer be locked in as the starter for left guard:

Chargers D! pic.twitter.com/Sm6mTJhmxG

- Jason Delgado (@JasonDelgado78) August 18, 2026

Shanahan said, It's still a competition. No one has really completely made it easy on us yet. I still think we've got a lot more time to go. Not a ton, but enough for guys can step up and do it. I think Carver missing that time made him a little bit behind the 8-ball on it, but it's good that he's gotten a full week in. Hopefully, he has no setbacks so we can make that opinion here in two weeks."

De'Zhaun Stribling scored in the red zone:

De'Zhaun Stribling just had a pair of TDs in the red zone. This is the first. @CamInman has a shot of the second. pic.twitter.com/4UjN2yTp9d

- Matt Barrows (@mattbarrows) August 18, 2026

If he can catch these fade routes, the red zone offense will be difficult to stop:

Sick touchdown catch by #49ers WR De'Zhaun Stribling

@CamInmanpic.twitter.com/YAHsBtFRj5

- (@TheSFNiners) August 18, 2026

Here's Deebo slipping on a slot fade:

Maybe 5 years ago.... pic.twitter.com/9Y1klhOZ5r

- NFLMike (@TheNFLMike) August 18, 2026

Shanahan said he liked how the offense performed at first, but not so much later on: I thought we struggled a little bit in the move the ball periods. Didn't score in two-minute. There were some ups and downs. I didn't really like how we finished the day."

Brock Purdy said, Honestly, I don't think it was our best day. I just feel like we could have come out with a little more chip on our shoulder."