Kyle Shanahan had to learn about Kwon Alexander the hard way.
"He taught me a hard lesson that you'd better game plan for him," Shanahan said during Alexander's introductory press conference on Thursday.
In Week 1 of the 2016 season, the Atlanta Falcons fell to the Tampa Bay Buccaneers, 31-24, in their home opener. The Buccaneers defense managed to hold Atlanta's running back tandem of Devonta Freeman and Tevin Coleman to just 42 combined rushing yards. Alexander, a second-year linebacker for Tampa Bay at the time, was a menace against Shanahan's offense.
That game, Alexander put up a career high 15 solo tackles, a sack and two quarterback hits -- numbers that left unpleasant memories for Shanahan.
"It was so bad that (Atlanta Falcons wide receiver) Julio (Jones) asked me after the game if he could play fullback and block him. So I knew I needed a better plan the next time," Shanahan laughed.
That familiarity played an integral role in the San Francisco 49ers interest in the free agent linebacker. So did Alexander's speed, athleticism and ball skills that fit the makeup of what John Lynch seeks in an off-ball linebacker. Despite coming off a season-ending ACL tear, the 49ers are hopeful Alexander will return to his usual level of play in 2019.
Alexander's leadership was a final selling point for the 49ers.
"There were a lot of good linebackers out there this year," Lynch said. "Kwon, I think I've long admired. I believe certain players bring out the best in their teammates with the way they play. There's a certain passion for the game that screams even when you're watching film that's silent. You can just see it jump through. He plays with his hair on fire. I think that kind of play is contagious. We needed that."
This year at the NFL Combine, Buccaneers general manager Jason Licht referred to Alexander as the "heartbeat" of Tampa Bay's defense. In 46 games with the Bucs, Alexander amassed 380 tackles, 22 passes defended, 17 quarterback hits, seven sacks and two fumble recoveries. He added six interceptions and six forced fumbles during that time span.
One of San Francisco's points of emphasis heading into 2019 was upgrading a defense that ranked dead last in takeaways. The 49ers forced a league-low seven turnovers in 2018. San Francisco anticipates the addition of Alexander will help remedy one of its most glaring deficiencies.
"He's always around the ball," Lynch added. "There's so many things to like, but that is definitely something that jumps."
Added Alexander: "I like to go get the ball. It's contagious. (If) everybody sees me go get it, they're going to want to go get it. As long as we're building and we're on the same page and communication is great, we're going to go get that."
The linebacker said he's taking his current rehab day-by-day but is hopeful that he'll "be back soon." Upon his return, Shanahan will be eager to see Alexander be a thorn in the side of opposing offensive coordinators.
"I've got something to tap into," Alexander said. "It's going to be amazing. You're going to see it the first game whenever I get to play."