SANTA CLARA, Calif. — Romello Height knew there was something about fellow San Francisco 49ers rookie De’Zhaun Stribling.

Did Height know that, like his own father, Stribling’s dad was a Marine?

“Ahhh,” Height said after practice Thursday, nodding his head. “I can tell. He’s just one of those mature young guys that takes care of his body and lives in the facility. He’s got a good routine going on already, has always done his homework and stands out in practice.

“That’s a huge deal. I respect him.”

It takes one to know one, and like Stribling, Height is a mature — 25 years old! — rookie, having attended four colleges in six years before turning pro. The 49ers are counting on the third-round pick to help their pass rush opposite Nick Bosa, and there’s no real Plan B.

Height’s speed and twitchiness jump out. Niners defensive coordinator Raheem Morris tried to tone down his enthusiasm the first week of training camp, saying the players weren’t in pads yet … but they have been since last Friday and …

A big smile hit Morris’ face Thursday.

“He’s a smart young man,” Morris said. “He’s the guy you’re scared to talk about early, when you watch him move around in shorts, because it’s not real football yet. Then you got a chance to watch him in pads …

“You got a chance to see his physicality and some of the things that he can do — particularly rushing the passer, setting the edge. Then you get a chance to see a little bit of versatility out of him. So, you’re excited about his ability to go out there and play at a very high level.”

The 6-foot-2, 239-pound Height had his first “Welcome to the NFL” moment last week when he squared off against future Hall of Fame left tackle Trent Williams in a one-on-one drill. To say Height ran into a 6-5, 320-pound wall wouldn’t do it justice. That wall moves quickly. And it leaned on him.

“That’s what I need,” Height said, smiling. “I need that every day, to sharpen my skills. Trent is the most athletic tackle ever, so that’s going to happen. I might get the best of him someday.”

Height bounced back later in the drill, using a dip move to rocket past rookie tackle Enrique Cruz Jr.

Height showed he could rush the passer last season when he had nine sacks at Texas Tech, his fourth college stop. He knew he could make the NFL way back in his freshman year at Auburn. It just took him a while to find the right path.

“I realized what I had, and it was speed,” Height said. “It’s been speed from the jump, and it was different. I would go up against some good really good players at Auburn — I was on the scout team — and I got scout team player of the year my freshman year. So that’s honestly when I realized, ‘Man, I got it. All I gotta do is just continue to stack the days, work hard and my time will come.’ ”

He transferred to USC, where … well, let’s not criticize a young man too much for having fun, but Height began having trouble showing up on time for classes and team meetings.

“I was just all over the place, and I knew I had to change and mature in so many ways,” Height said.

He often thought of his dad, Ronnie, the ex-Marine.

“If he could have gotten his hands on me around that time, he probably would’ve strangled me,” Height said. “I got caught up in a lot of stuff, and that wasn’t how I was raised. I had to find myself, and once I did, man, I was on the right road.”

The next stop was Georgia Tech, close to home in Dublin, Ga. Height loved it there.

“They told me as soon as I came in the building, like, ‘Mello, just get off of the ball and play how you want. Go get the quarterback or whoever has the ball,’ ” Height said. “They fit the scheme around me.”

He would have stayed at Georgia Tech, but like a far-off dinner bell, the pull of NIL was drool-inducing.

So, Height became a Texas Tech Red Raider, and the school got its money’s worth — a player who was the product of his father and his previous three stops.

“Four schools is a lot, and I was just trying to find myself,” Height said. “All those stops came with maturing. And by the time I got to Texas Tech, I was a totally different person.

“I was taking care of my body. I was living in the building. I was creating bonds with my teammates. I was finally the best version of myself.”

NFL teams didn’t care that Height went to four schools or that he was 25. The pass-rush highlights would get anyone excited. At the NFL Scouting Combine, he posted top-five numbers in both vertical (39 inches) and broad (10-5) jumps. In the draft, he fell to the third round because of his slight frame and concerns about how he would hold up in the run game and get off blocks in the NFL.

The 49ers, Morris said, saw someone who might be able to move around, maybe even drop back in coverage when he wasn’t setting the edge. And don’t sell Height’s pass-rushing skills short. That’s a huge need for the 49ers.

“I’ve never seen a (rookie) come in and get the scheme as quickly and seamlessly as he has,” Bosa told KNBR radio. “Even when vets come in who haven’t played in this scheme. He’s gotten it even quicker than I did.

“He’s super explosive. He’s got a bag of tricks in pass rush that you could tell he’s been coached well. He’s a little older for a rookie, so that might be part of it, but I think he’s going to contribute pretty quick.”

Height credits the staff at Texas Tech with stuffing his bag full of pass-rush moves, especially the chop. During training camp, he has been focused on making blockers pay for being on their heels waiting for a speed rush.

“I’ve been just trying to throw power in my tool bag,” he said. “That makes tackles more vulnerable to inside moves, more vulnerable to the speed that I’m gonna use because they’re just gonna sit on speed if I’m just showing continuous speed.”

He has a great sounding board in Bosa, who has been working on the side during camp as he approaches his return from knee surgery.

“I love picking his brain about techniques, the get-off, alignment, your assignments, everything,” Height said.

Mykel Williams, last year’s first-round pick, is a little behind Bosa in his own return from knee surgery. But at some point, the plan is for Bosa and Williams to start on the edge, and then — on passing downs — to move Williams inside and have Height come in and fly around.

“We drafted him to rush the passer, and he’s really excelled at that,” defensive line coach Kris Kocurek said. “His get-off has been really, really good, being able to put tackles behind the 8-ball with his get-off and making them set differently and protect differently and getting on them quickly.”

Height can’t wait to put the uniform on for real for the first time in next Thursday’s preseason opener against the Tennessee Titans.

“I’m itching, but I can’t try to get ahead of myself,” he said. “I gotta continue to take it day by day up into that game. Don’t try to do too much, don’t do too little.”

His dad and a rookie teammate would give him a nod of the head. It took Height a while, and a lot of packing and unpacking, but he has his routine down now.