HOUSTON — Dave Canales wanted heat. He got it.

The Panthers' joint practice with the Texans was predictably a scorcher, with temperatures in the low 90s early in the morning, and dew points pushing into the high 70s (weather geek for really, really humid).

And Canales wanted that kind of work to be ready for the regular season opener in Jacksonville, where it's also known to be swampy. What he didn't want was a block of about five pre-snap penalties in the middle of practice, that started them in some first-and-15 and second-and-20 spots.

"Fatigue, lack of focus, that's something that we have to learn to do better," Canales said. "We have to be able to fight through fatigue, fight through exhaustion, it's going to be hot. We're going to go to Jacksonville in Week 1. It's going to feel like this.

"Can we maintain that level of focus play after play, regardless of what the last play did? Can you breathe on your way back, and then can you execute? And I saw the penalties pile up when we were tired. That's something that we have to get better at."

Otherwise, he liked the work against a talented Texans team, which has won 10 games each of the last two years, along with AFC South titles.

Canales was focused on the offensive field, as is his custom, so he saw both of his first two offensive units get into the end zone to close practice, with Bryce Young hitting Ja'Tavion Sanders, and Andy Dalton connecting with Hunter Renfrow for scores.

"I thought it got sloppy in the middle, responded at the end with two great two-minute finishes for touchdowns at the end of the practice over here, which was phenomenal," Canales said. "And I just keep convincing our guys that's who we are. We finish. Games can get ugly in the middle. We have to be able to focus and rebound. So I was really excited about that part."

Injury and availability updates on Nic Scourton and others

Rookie outside linebacker Nic Scourton, a Texas native, had to leave practice midway through because of the heat.

The athletic training staff quickly got him into the cooling trailer in the end zone to begin the treatment.

"They got him in there, tried to get his core temperature back down, he had to take some IV fluids, and we just didn't feel comfortable putting him back out there to finish the practice," Canales said. "You get dehydrated, the first thing that happens is you get soft tissue injuries, but they did a good job of catching that, getting him in there, cooling him down.

"We'll get him some more fluids, and hopefully we can get him turned around so he can play in the game."

Cornerback Jaycee Horn didn't practice, which was anticipated because of the stitches in his left thumb from last week's car accident. Canales said he wasn't expected to play in Saturday's preseason game because of it as well.

Wide receiver Jalen Coker stayed back at the hotel with an illness. Canales said he had a fever and swollen lymph nodes, so they were treating him with antibiotics for an infection, and they haven't ruled out getting him on the field Saturday.

Linebacker Trevin Wallace arrived during practice, but didn't participate. He did not fly with the team Wednesday because of a personal matter.

Otherwise, the normal group of rehabbing players worked on the side, with Chandler Zavala, Tommy Tremble, and Claudin Cherelus joined by rookie defensive tackle Cam Jackson.

Defense turns into ballhawks against Texans' offense

The ball was trading hands all day while the Panthers' defense went up against the Texans' offense in joint practice. Canales and crew have put a significant emphasis on creating turnovers in the defense and winning the turnover margin. So on Thursday, both the ones and twos went after the ball.

During an early team run, newly acquired linebacker Krys Barnes dropped into coverage, found a soft spot, then jumped in front of a Davis Mills pass as if it was intended just for him.

As the groups moved into a red zone drill, Stroud loaded up, looking for Christian Kirk on what would've been a long pass for a touchdown. But Mike Jackson went seeking, peeling back off his guy to track the ball, and timing his jump on the high pass perfectly, coming down with the would-be touchback.

The defense wasn't done yet. The very next set of reps, Mills took back over and threw into a scrum in the end zone, hoping his tall receiver could come down with it. Instead, safety Nick Scott batted the ball into the air, knocking it away from the receiver, and then positioned himself to catch the ball as it floated back down, adding another interception to the day.

"Man, I saw a lot of energy," said safety Tre'von Moehrig. "The guys flying around the ball, being physical, took the ball away a couple of times, so I thought we had great energy coming out here and had a good practice."

Added outside linebacker Patrick Jones II, "Anytime you get a pick in the red zone, that's big time. So I mean it's just so great knowing when I'm rushing, I got players like that behind me and just keep making plays like that."

Panthers test linebacker rotation without Wallace

The Panthers were without Trevin Wallace on the field during practice against the Texans. The second-year linebacker flew into Houston on his own Thursday morning after what Canales referred to as "a personal matter." Wallace did come straight to the practice facility, jogging out to meet his teammates mid-way through practice, but it was too late to suit up for the day.

Instead, defensive coordinator Ejiro Evero was able to test out some of the linebacker depth alongside Christian Rozeboom. Jon Rhattigan and Thomas Incoom took some of the early reps with the first team. Then, rookie undrafted free agent Bam Martin-Scott got in with the ones and stayed for most of the day, except for a few specific packages.

Canales said Wallace will play on Saturday.

Will the real Adam Thielen please stand up

As each Panthers player stepped onto the field Thursday morning, the Texans fans in attendance welcomed them accordingly, with boos and jeers (even the non-players got booed if they were wearing black and blue). Running back Chuba Hubbard ate it up and egged it on as he walked across the field with arms raised, asking for more.

But two Panthers' defensive guys received a bit of a different welcome. As Rozeboom and Rhattigan walked onto the field together, a Texans fan—actually excited to see a player he knew and liked—began screaming out, "Adam! Adam Thielen," trying to get the attention of two players, neither of whom was Adam Thielen. Playing along, Rozeboom looked at Rhattigan, asking if he was the Adam the fan wanted to meet, before turning back to the fan and quipping, "no, just the other white guy."

No word on if the fan ever met the actual Adam Thielen.

Big play from an unlikely source — England

One of the plays of the day came from an unlikely source.

Linebacker Mapalo Mwansa, the Panthers' English exchange student, forced a fumble during a kickoff coverage drill.

It was a huge moment for the 21-year-old, who can stay here on the practice squad with a roster exemption since he's part of the league's International Player Pathway. (You can read his full backstory, and it's inspirational, here.)

"That was big," Mwansa said as he left the field, with a huge smile on his face. "Now just have to keep working, keep learning, keep stacking days."

He's been playing football for months, not years, and after his early work came as a pass-rushing edge player (because of his speed), the Panthers shifted him inside to linebacker (because of his size, since he's 6-2, 230). That's right, they gave a guy who hadn't played the sport until around a year ago the most complicated position to learn. Good luck, Maz.

But where he can make a name for himself is on special teams, where he can take advantage of his speed (he ran a 4.45-second 40 at a CFL combine). And plenty of players have made long careers out of that alone.

He's still swimming as hard as he can in the deep end of the pool, but making a play on this stage was big for him.

Panthers came out of the practice healthy

Other than Scourton leaving because of the heat, the Panthers came through the joint practice in good shape, which is always the best news.

And considering the massing shift in weather — it's been rainy and mostly cool for over a week back home — that's saying something.

"It's been a little unseasonably cool. I know we've kind of been spoiled with the weather a little bit," Canales said. "But I felt confident about our conditioning level. I think that we're dosing the guys the right way, pushing them a little bit beyond their limits every day and trying to increase their workload. This was a crescendo of the hard work.

"I love that we were able to come out here to play all the way through, finish with great two-minute drives over here. For the most part, this is a very fit group that's ready to play football. I love the fact that we got this heat. Again, it's football. We'll be prepared for it. We let the guys know, go out there, give everything you have. If we see that you're gassed, we'll get somebody else out there. And that's where the depth that we're building here is so important as we continue into the season."