A lot was made of the job Robert Saleh did for the San Francisco 49ers last season, patching up an injury-maligned defense and helping win a playoff game. It got the defensive coordinator the call to be the head coach of the Tennessee Titans.His replacement, Raheem Morris, has wasted no time making his own impact. Besides introducing more five-down-lineman looks, Morris has defenders attacking from different angles, and the 49ers’ pass coverage has been noticeably tougher during the first couple of days of training camp.When quarterback Brock Purdy drops back to pass, receivers not named Mike Evans aren’t exactly breaking free from defensive backs.“Raheem’s done a good job of coaching up our DBs in terms of being sticky … and that match coverage, it’s real,” Purdy said after practice on Monday. “They’ve done a really good job with it. I think we have the right personnel on the defense to play that kind of defense.”Add in linebacker Fred Warner being reunited with Dre Greenlaw underneath at linebacker and …“Those windows are tight,” Purdy said. “When the defense does a good job of having tight coverage and tipping the ball up in the air, it’s real. … We’re all just going to continue to install more stuff, and hopefully the competition level just keeps getting higher and higher.”How Fred Warner is preparing to bounce back from injuryDan PompeiWarner likes that the offense is on its toes, after mostly going against traditional four-linemen, three-linebacker looks over the years.“Now we’re having some of those five-down looks, different coverages and things of that sort,” Warner said. “It’s new for all of us. We’ve all got to learn on my end, and obviously for them, they can’t just be like, ‘Oh, I know exactly what they’re running and let’s just book it up.’”Morris, who turns 50 next month, is coming off a three-year stint as head coach of the Atlanta Falcons, and though he has a long history with 49ers coach Kyle Shanahan, this is his first time in the building. Everything he heard about the culture and the veteran players has been proven true.“The guys that we have on our roster are just obsessed,” Morris said. “They crave more information, they crave energy, they crave the ability to go out there and learn every single day. … This is not my defense. This is the defense we’re building that’s built for the Niners and what we’ve already had in place, what we’ve done or what they’ve done, what I want to be a part of and move forward from there.”Morris was groomed in Monte Kiffin’s Tampa 2 defense from his days as a young assistant on the Buccaneers, but he also liked to make his defensive backs interchangeable to confuse quarterbacks. As defensive coordinator with the Los Angeles Rams from 2021 to 2023, Morris incorporated more two-safety shells, different fronts and coverages after taking over for Brandon Staley.He sees the field especially well. In his first stint with the Falcons (2015-20), Morris spent four years as the wide receivers coach, doubling up as the defensive backs coach in 2019.“He understands both sides of the ball, and while his scheme shifts, he’s always aggressive,” one NFL offensive coordinator, who was granted anonymity so that he could speak freely, said of Morris via text. “He is very smart and has a good rapport with players.”Morris has already been hands-on with his new defensive backs, including new veteran Jack Jones, the former Patriot, Raider and Dolphin who had a nice pass breakup Monday.“Jack has been known as a playmaker, and he’s also been known to give up some, right?” Morris said. “So, you have the ability to get him out there and teach him some fundamentally sound things.”He wants his defensive backs to be aggressive but not guess.“Making plays is just technique and opportunity meeting,” Morris said. “(Jones is) one of the better ones at it when he’s in those meeting rooms listening to it.”A good pass rush is key to any coverage plan, especially a physical, aggressive one. Rookie defensive end Romello Height has been getting first-team reps with Mykel Williams on the mend and Bryce Huff retired.Height was carted off at the end of Monday’s practice, but everyone was relieved to see it was merely a severe case of cramps. Teammates and coaches have been impressed with the lean 25-year-old rookie.“A guy with a high capacity,” Morris said. “Obviously, a guy with great energy. He brings a lot of juice to us and brings some things to us that we needed. … Obviously, there’s always kind of putting the cart before the horse when you talk about upfront people before they actually play the game, but he’s done a nice job for everything that he’s had to test for right now.”Height has been leaning a lot on veteran Nick Bosa, who is back from a knee injury … though not quite. Bosa is cleared to practice but has been working on his own during the first few days of training camp. The 49ers have always let the veteran go at his own pace at camp, and he looks great — better than he did before his injury, according to left tackle Trent Williams.“To watch that guy and what he’s able to do, the amount of power he plays with, the speed, the presence, he’s one of the calmest players I’ve ever been around in my life,” Morris said of Bosa. “And he brings this certain ease and a certain ability to move just effortlessly every single day.“He’s limited and working his way back, but he looks excellent. That’s always a good time for us.”When Bosa gets going, Morris will be able to have fun with the five-down looks, where a rusher might drop back and have someone else rush in to confuse the quarterback.