The San Francisco 49ers will be guests in the Los Angeles Chargers’ El Segungo facility this week for their second joint practice of the preseason.

They’d better be on better behavior than when they welcomed the Tennessee Titans last week … by instigating a half dozen skirmishes, including a handful in the first few snaps.

The two-week countdown to the Niners’ departure for down under officially begins at the conclusion of Tuesday’s joint practice. The regular season is right around the corner.

It’s time to put the extracurriculars behind them and turn the focus to football.

“We’ll see if we can go out there and have a more composed practice and play a little bit better and play faster and do some different things that we want to do,” defensive coordinator Raheem Morris said. “I think it’s just a steady process to get to that first game.”

Morris’ unit was responsible for most of the hubbub last week. The Niners’ defense came out firing on all cylinders — too many cylinders — that led to time-wasting dustups and, more consequentially, two players eventually being tossed out for throwing punches.

That’s a pair of potentially productive practices gone down the drain.

“You don’t really care about scuffles. You just hate losing guys,” head coach Kyle Shanahan said. “The player loses all the reps for the day and then your position’s down for the whole day, so that usually can be a chain reaction to other guys. That’s why we don’t want that to happen.”

Some sparring is inevitable. After all, this is football. Violence is the point.

But every second spent clearing the air after a scuffle is another snap lost in some of the most valuable situations for a coach to evaluate his football team in the preseason.

“You want them to have their edge, but there’s a certain amount of work that you want to be able to get done,” Morris said. “You want to have the ability to take it to that edge and walk that line but be able to play the game and be able to get the stuff they want to get done. Composure is about everything that we do in our game, so it’s just one of those things. 

“You’re not worried about it at all. You just want to be able to take it to joint practices, right? We’ve seen these guys play a bunch of games, a lot of these guys. And so, I’m not worried about that one bit. But in practice, let’s use that same demeanor, that same temperament.”

49ers real test before NFL season

One reason why San Francisco’s starters came out with so much gusto in last week’s joint practice was because they knew they weren’t going to play in the preseason game two nights later. The same goes this week. Tuesday is the true test for the players that matter.

“The joint practices are really the big measuring stick,” offensive coordinator Klay Kubiak said. “That’s where we know we have a plan about how many reps guys are going to get. We know what we’re going against. That’ll be set going into that practice. That’s a big day for our team.”

Justin Herbert should provide the stiffest test yet for the 49ers’ secondary, which so far has looked like their strongest group of camp. Brock Purdy will attempt to live up to his new nickname — “The Layer King” — against a defense led by Derwin James Jr. that yielded the fifth-fewest yards in the NFL last season.

Coaches will be paying especially close attention to the trenches, where Robert Jones, Carver Willis and Connor Colby all take snaps against the Chargers’ first-string defense trying to gain the upper hand on the depth chart at left guard in the top position battle left in camp.

You won’t see that Thursday night.

Shanahan spent a portion of the first joint session chatting with Saleh, his former defensive coordinator. He figures to have some catching up to do with Chargers offensive coordinator Mike McDaniel, an assistant his first four seasons in San Francisco.

(Side bet: How many words does he share with Trey Lance, now the Chargers’ backup QB?)

The Niners haven’t taken part in many joint practices under Shanahan before this year. But with his former assistants now floating about the league, some of the logistics are easier.

They also give him an impartial and trusted source to point out his team’s flaws. He can give them the same kind of unfiltered notes, just as he would if they were still on his staff.

It helps that both Saleh and McDaniels’ current employers are in the AFC.

“We’re not the biggest note takers, but we’re more FaceTimers,” Shanahan said of him and Saleh. “So, we sat there and FaceTimed a little bit the last two nights, just talking about what we saw from each other. It’s a little bit easier when you’re in different conferences. You don’t have to lie as much.”

Let’s just hope they have football to talk about this week, not a cage match.