TAMPA, Fla. -- After firing defensive line coach Jay Hayes, signing Beau Allen, Vinny Curry and Mitch Unrein, trading for Jason Pierre-Paul and drafting Vita Vea, all eyes are on the Tampa Bay Buccaneers' new defensive line coach Brentson Buckner to transform a unit that produced a league-worst 22 sacks last season and plays in one of the toughest quarterback divisions in the NFL.

Buckner has already started to leave his mark -- first with an assessment of the Bucs' current roster. In some cases, there have been doses of brutal honesty, the type that is absolutely necessary when a defense gives up more yardage than any other team in the league, which Tampa Bay did last season (378.1). It has been the type of honesty that resonates with current players, because for 12 seasons as a member of the Pittsburgh Steelers, Cincinnati Bengals, San Francisco 49ers and Carolina Panthers, Buckner taped up his fingers and subjected his body to the same weekly punishment that his players do.

He told six-time Pro Bowler Gerald McCoy, who has had to carry the defensive line for eight seasons and has yet to appear in a playoff game, to embrace the new talent around him. McCoy has help now and doesn't have to do it all himself. Buckner told him, "I don't need a Superman. I need a whole bunch of Super Friends that can work well together," adding that it was also time for McCoy to adjust his approach.

"You get to the point of being 30 years old -- it's not about your ability now, it's about playing the game up here," Buckner said, pointing to his head.

"I sat down and watched film with him and I told him, 'The way you're going to improve your game is to mentally evolve your game even more.' And he wants it. He's hungry for it, because for nine years, eight years, he's done the same thing and been successful but it hasn't shown up for the team. So now I'm challenging him personally to go to that next level. Not get stronger, not get faster -- play the game up here. Know what they're going to do to you before it happens. Be smarter about it."

Then there's defensive end William Gholston, who, after signing a five-year contract extension worth up to $37 million last offseason, failed to produce a single sack in 2017. He told Buckner, "I felt like I got a little too big last year."

"I was like, 'Now that you know that, do something about it,'" Buckner said. "He's actually 15 pounds lighter right now. He's been working to evolve himself mentally, too. Because the hardest thing you can do as a player is to look at [yourself] and be critical of [yourself].'

"I tell them all the time, 'You've gotta be more critical of yourself than me. If I care more about it than you, then it's an imbalance.' ... Everybody has a down year. But it's the way you bounce back. But I think he has a chance to bounce back and be who he wants to be."

Allen appreciates Buckner's direct approach and the fact he is so easy to relate to.

"When you see a guy who's played in the league for 12 years, you know he's tough, you know he understands the NFL culture, the culture of a defensive line room and the locker room, and you can have real football conversations and real talks with him because he understands what it's like to be a player and be out on the field," Allen said.

Buckner has already made his mark in Tampa in other ways, including recruiting Curry when the Philadelphia Eagles released him in March. "When I talked to him on the phone, it seemed like he had a manual out on me," said Curry. "It was like, 'OK, this guy understands Vinny Curry.'"

Allen added: "He does his homework and he cares about the game of football."

That's part of Buckner's meticulous attention to detail, something he credits the legendary Bill Walsh for instilling in him. Walsh was president of the 49ers when Buckner played in San Francisco, and Buckner saw how Walsh's mental edge helped the Niners win games.

Under Buckner, there will also be a heavy dose of fundamentals, although he tries not to get carried away with drills if he doesn't believe there's a direct correlation to performance on the field. His first defensive line coach when he was with the Steelers, John Mitchell, taught him that.

"He used to always say, 'Believe in the dark what is said to you in the light,' meaning, trust that when I tell you fundamentals are going to work -- when it gets dark out there and you're tired, and it's hot and [you] can't go [any farther], fall back on your fundamentals," Buckner said.

"But you have to have worked on them so much that you can trust going back to them."

Then there were the 7- to 9-year-olds he coached at Northside Christian School in Charlotte, North Carolina. They helped Buckner develop as a teacher, and taught him the importance of catering to different learning styles, something he still uses today.

"They taught me [that] everyone wants to play this game but everybody learns at different levels," Buckner said. "I had to have 27 different coaching plans to get the best out of each kid. And so when I come into a room with 12 people -- Vinny learns different from Gerald, Gerald learns different from Beau. My job is to get each one of them the information they need and get them to galvanize and come out and play together."