EL SEGUNDO, Calif. — Besides a walk-through and a few meetings, the San Francisco 49ers have essentially an off-day at the hotel Wednesday before they play the Los Angeles Chargers in a preseason game Thursday night.

For the defense, that will be more time to reflect on what could not have been a fun film session following Tuesday’s joint practice at the Chargers’ facility.

Los Angeles quarterback Justin Herbert did whatever he wanted, throwing deep to Quentin Johnston and Brenen Thompson, across the middle to Ladd McConkey and even across his body as he scrambled right for another touchdown pass.

What’s really going to sting the collective pride is running back Omarion Hampton trucking not one, but two 49ers defenders in practice. The speedy Hampton showed his power by sending safety Ji’Ayir Brown and rookie linebacker Jaden Dugger flying on runs.

For the optimists out there, a few of the big plays wouldn’t have happened in real life. The 49ers did get some pressure on Herbert, and sacks aren’t allowed in scrimmages. If they were, defensive tackle Osa Odighizuwa would have had about six.

Trading for the former Dallas Cowboy was one of the best moves the 49ers made this offseason.

“It just seems like he just keeps getting better and better, right?” linebacker Fred Warner said after practice. “I love the mindset, the tenacity, the physicality that he brings to the position and to our defense. We know how important it is to get pressure up front on the quarterback and in the run game.

“I think he’s just gonna continue to get better as we keep going.”

Undrafted rookie defensive tackle James Thompson Jr. built on a strong training camp with some powerful rushes up the middle and a tackle for loss in the running game.

Ogbo Okoronkwo also had what would have been a sack, while cornerback Jack Jones had his daily pass breakup and Renardo Green was solid compared to the rest of the defensive backs …

Enough of the positivity. Here’s a summary of all the carnage on the defensive side:

• The 49ers might have been lulled into a sense of overconfidence coming off last week’s joint practice with the Tennessee Titans. The Chargers are a different animal, starting with their physical offensive line — tackle Joe Alt finished one block on a touchdown after his helmet was knocked off — bazooka-armed quarterback and quick receivers.

The Niners might have known they were in for a long day when they were surprised that Chargers offensive coordinator Mike McDaniel started with unbalanced formations.

• Thompson beat cornerback Deommodore Lenoir and Brown deep right out of the gate, although an Odighizuwa sack would have prevented it in game conditions. Johnston made a one-handed catch deep down the sideline as Lenoir grabbed him and was called for pass interference. Johnston would stop soon after, tweaking his ankle, while center Tyler Biadasz was carted off after sustaining a leg injury, but the Chargers’ offense didn’t miss a beat.

• There were also a lot of soft spots in the middle of the defense, as McConkey slipped free, and Hampton and fullback Alec Ingold each had some big gains on checkdown passes.

McConkey caught a touchdown pass while being held by Jones. He was also the recipient of that ridiculous across-the-body throw by Herbert mentioned above. At that point, the Chargers were scoring on four straight plays during the red zone scrimmage. Tight ends ran free like voodoo-induced kids in a small town after midnight.

• Brown did get revenge on Hampton by lowering his shoulder to hit the running back into the sideline when he tried to turn the corner. That got a rise out of the 49ers defenders, but it was too little too late.

Warner said he didn’t notice if it was that bad for his defense.

“It’s hard to tell, when you’re in the battle, what’s exactly going on,” he said. “You’ve got to see the tape to really see what it looks like. But any time you get to go against another team, it’s a great opportunity to see where you stand.

“Luckily, it was a good test for us.”

And it seems like pass rusher Nick Bosa (knee) might finally be back for Saturday’s practice, while defensive end Keion White (adductor) returned Tuesday. (Coach Kyle Shanahan said, though, defensive end Mykel Williams likely won’t be back by the season opener as he continues to rehab a torn ACL.)

So, things are looking up. Some of the starters will get a chance for some payback Thursday night, as Shanahan said he won’t rest many of them.