SANTA CLARA – Nick Bosa propped himself up with his right hand on the grass. He stretched back his right leg and surgically repaired knee. Then, in a flash, he shot into a blocking pad to lead off the 49ers’ first defensive line drill of training camp.

That is a not-so-subtle reminder the 49ers’ pass rush will improve this season. It tanked without Bosa last season, once he exited with an anterior cruciate ligament tear in their home opener.

Five years after recovering from his left knee’s ACL reconstruction, Bosa’s comeback this season is the 49ers’ best hope at racking up more sacks, no matter how much chaos is created around him by defensive coordinator Raheem Morris’ aggressive and less predictable scheme.

Bosa isn’t yet in full-team drills but he’s made an eye-opening return to defensive-line warmups.

“He’s one of the calmest players I’ve been around in my life,” defensive coordinator Raheem Morris said. “He has this ease and ability to move effortlessly. He’s working his way back but he looks excellent.”

Bosa, without a brace or support sleeve on either knee, warmed up on a side field before Sunday’s first practice at camp. The 2022 NFL Defensive Player of the Year showed no hints of a hitch in his giddy-up as he regains the strength he’ll need this season, which starts in seven weeks in Australia against the Los Angeles Rams.

“I can’t even tell that he had an injury or he came back from anything,” left tackle Trent Williams said. “You know, most people with a knee injury that catastrophic, you come back, you can see something, right? You can see it in the atrophy in the muscle in the leg. You can see something.

“Bosa looks better than he did before he got hurt last year,” Williams added. “So, that’s just a compliment to him and how hard he works. A guy that successful with that much, for his motor to still run as high as it does, it’s just a testament to his character.”

Bosa acknowledged his football mortality crossed his mind after last September’s ACL tear during a pass rush against the Arizona Cardinals.

“You start out wanting to quit, never play again and never put your body in that position again,” Bosa, 28, recalled in March. “Then slowly you realize that you love this game and you want to get back to it. I mean I’ve never doubted I can get back to where I am.”

Rather than being rushed into team drills, Bosa stayed on the side field Sunday with lead trainer Dustin Perry. Meanwhile, rookie Romello Height and veterans Keion White and Sam Okuayinonu served as the top defensive ends; Mykel Williams, last year’s first-round pick, is on the Physically Unable to Perform list because of his midseason ACL tear.

“Nick is one of the hardest workers and a guy who’s so in-tune with his body,” linebacker Fred Warner said. “Having gone through that injury before, he obviously knows the steps and things that he has to accomplish in order to get back on top and be the guy that he’s always been.”

Bosa has openly pined for years to play alongside his older brother, Joey, who is a free agent after 10 years in the league. But such a 49ers union remains remote, with Nick Bosa telling KNBR 680-AM on Monday that it was “probably not” in the works.

One Bosa is better than none, as the 49ers sure learned again last season.

“He’s one of the best players in the NFL, so to have him back on defense creating pressure is a big help to us,” cornerback Deommodore Lenoir said.