The 49ers' blockbuster trade that sent Buckner to the Indianapolis Colts in exchange for the No. 13 overall pick of the 2020 NFL Draft eventually netted the club former South Carolina defensive tackle Javon Kinlaw with the 14th pick.
Bosa spoke to local Bay Area media on Wednesday and expressed confidence that there still is a lot of leadership on the team but there are certain things that Buckner brought to the table that he personally will miss.
"Buckner is definitely one of my best friends on the team and seeing him go was obviously bittersweet," Bosa said. "He's obviously got a pretty big contract and he deserves it but just losing him as a leader we're going to have to really figure out how to step up and fill that void."
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Buckner's role on the 49ers defensive line was unique. While linebacker Fred Warner made the defensive calls with the "green dot," hearing the communication from the coaching staff, Buckner made the third down calls sent in by defensive line coach Kris Kocurek.
"We would turn to [Buckner] on third down for our third-down game calls. Coach Kris would point and tell us that we were running something and we would walk up to Buck and be like, ‘Whatcha got Buck, what do you want?'
"And if Kris didn't specifically say something that he wanted, then Buckner would just decide. That's a pretty big responsibility that we're going to have to pick up."
Without Buckner, the 49ers defensive line room still has a lot of experience. Arik Armstead, Dee Ford, Solomon Thomas, D.J. Jones and Ronald Blair round out the group that will help Kinlaw adjust to life in the NFL.
Bosa knows that even in his sophomore season, he and the other members of the 49ers' 2019 rookie class have their work cut out for them. There is no time to waste stepping up into a leadership role for the likes of Bosa, the Defensive Rookie of the Year, receiver Deebo Samuel and linebacker Dre Greenlaw.
"We're not just deers in headlights anymore," Bosa said. "We know the routine, we know how an NFL season works and now we can really just take the next step and just work on honing our game and really studying our opponents now that we know, now that we've played them once."
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The intangibles that Buckner brought to the defensive huddle and locker room will be missed by staff and players alike. In his four seasons with the 49ers, he racked up 28.5 sacks while being an example of consistency in performance and attitude. He did so while playing 1006 snaps in his rookie campaign, and over 3500 in his four seasons in the red and gold.
"He was the hype speech guy, he was everything," Bosa said. "And I think he played with the best effort on the D-line, which really shows on tape when you see somebody that big sprinting to the ball every play and making those tackles down field. And obviously his pass-rush ability.
"We're going to have to step up we have obviously Javon coming in and I'm sure he'll be a huge help but me, Dee, Arik, Solly, D.J., Ronnie, we're all going to have to step it up for him."
49ers' Nick Bosa knows DeForest Buckner can't be replaced by one guy originally appeared on NBC Sports Bay Area