It was a position group that was re-fortified more than any other on the roster this past offseason. While those efforts were partly in response to a pair of free agent departures, Buffalo's front office, led by GM Brandon Beane, has proven to be very nimble in re-stocking the cupboard on the Bills defensive line. Whether it was experienced NFL free agents in the form of Mario Addison, Vernon Butler and Quinton Jefferson or promising youth in the form of A.J. Epenesa, Buffalo defensive front is arguably the deepest unit the Bills have had up front in more than a decade.

And while depth has its value for defensive coordinator Leslie Frazier, who rotates up to eight defensive linemen a game quite liberally, perhaps the most valuable asset is the group's versatility. Several of the nine defensive linemen on the roster have demonstrated an ability to play multiple positions along the front.

"You'd like to be able to constantly present matchup problems for an offensive line or for a protection philosophy," said new defensive line coach Eric Washington, who called a similar scheme in Carolina as defensive coordinator in 2018. "So if you have athletes that are versatile and they can commit to know the entire front concept and not just their position it makes their rotation that much more potent. It increases the value. We can have Mario Addison matched up in different places, especially if he has demonstrated that he can win from there."

Addison comes in with the most productive pass rushing resume with four consecutive seasons with at least nine sacks or more. That ranks 11th most in the league over that span (2016-2019).

"I really like the energy that Mario brings," said defensive coordinator, Leslie Frazier. "He's a well accomplished player in our league. He has some leadership qualities as well. I didn't know that, but I see that in his play and demeanor as well."

The other big addition, Quinton Jefferson, is also expected to line up at multiple positions through the course of the season. Though largely a rotational player in his time with Seattle, Jefferson has made a sizable impression on his new Bills teammates and the coaching staff during training camp.

"Quinton is a beast," said Addison. "He is one of those guys that he will fool you. You might think that he might not be able to play on the inside, or is too small to play inside, but when he gets in there, he's a beast. We've ran through one-on-ones, and I've had a lot of success rolling with him. I saw him on film, how good he was, but that doesn't mean anything until you see him in person. I am very glad to be playing beside him."

"Quinton just the toughness that he brings to our defense, a fiery guy who is ready to get after it from the time he gets off the bus," Frazier said. "So you like that edge that he brings to the defense."

As exciting as those additions are Buffalo's philosophy is to get to the quarterback with the front four and that means every man on the defensive front has to see himself as a pass rusher.

"One thing about this D-line is that we have depth," Addison said. "The ones are good. The twos are good. The threes are good. The coaches are doing a great job mixing everybody up with each other, the ones with the twos, two with the threes, threes with the ones. We won't have to rely on four pass rushers. Everybody is a pass rusher on this D-line. So, I'm already feeling at home already with the guys that I've been working with, and I'm happy to roll with everybody so far. Everybody's rolling."

For Jefferson, the depth on Buffalo's defensive front reminds him of his early playing days in Seattle.

"We were stacked," said Jefferson of his former Seahawk unit. "You're talking about me, (Jarran) Reed, Frank (Clark), Mike (Bennett), Cliff (Avril), and one year we had Sheldon (Richardson). It's definitely exciting to talk about and even here from top to bottom we might have more depth than from those years.

"Every day you've got to bring your A-game because of the other guys around you. I feel like it helps us, and we even have our little games where everybody wants to beat out the next guy. It's pretty cool, I feel like we're all going to push ourselves to that next level."

That daily competition has enabled the defensive line, which has seen more player turnover than any other position group on the roster, to jell quickly on the field and develop a feel for how to play off one another.

"We have a lot of guys in our room who are passionate about the game of football, understand how to be a pro, so it's going to be a lot of fun being able to play with those guys, pin our ears back and hunt some quarterbacks," said Jerry Hughes, now healthy after a pair of offseason surgeries. "We've got so many talented guys on our D-line and just watching everyone work and watching how we all been able to just click this offseason, even though we haven't really been with each other. That's been huge."

The Bills ranked 10th in the league last season in sack percentage, but they will have to make up for the loss of their top two sack producers in Jordan Phillips (now in Arizona) and Shaq Lawson (now in Miami). Addison's recent history certainly fills the bill. Hughes has back-to-back 10-sack seasons on his resume with the Bills, but that last happened in 2014 as he's played through injuries two of the last three seasons.

Frazier is excited about the combination of Addison and Hughes and the problems they can create for opposing offensive lines. Those two combined with the interior pass rush capabilities of Ed Oliver and Jefferson among others could be extremely productive.

"We're challenging all our guys to make this a career year and if Jerry and Mario can get back to their previous form coming off of an offseason that was so different than any other that we've ever experienced, that's going to be good for our defense," Frazier said. "They've put up some big numbers in the course of their careers so we're excited about having both of them and looking forward to them being on the field together."

Buffalo's team record for sacks in a season is 57, set in 2013 when the defensive line had three Pro Bowl talents in Marcell Dareus, Jerry Hughes, Kyle Williams and Mario Williams. They finished second in the league that year to Sean McDermott's Carolina unit, which had 60.

The same group for the Bills led the league the following year with 54. Coach McDermott will be the first to tell you that the sack total isn't the end all, be all figure. As long as there is consistent pressure on the quarterback to affect the timing of the offensive play, a defensive front is playing effectively. And he believes the best way to accomplish that is by relying on everyone to make contributions.

"I think it's really about fresh bodies and we've got a number of guys that we can roll in there which is which is good to have, many of whom have significant reps under their belt at this level," McDermott said. "I think the way that they work together and the way that group is coming together off the field is going to make them a good unit on the field. These guys are unselfish in their approach and they know that affecting the protection on their side can lead to a sack by somebody else on the other side. It may be a committee type of approach, which I'm totally fine with. I think that at the end of the day that the better defenses that I've been around are anchored by that defensive line and that committee approach usually serves it well."

The Bills men up front are also buoyed by the anticipation that their offense will take another step forward in their point production this season with Josh Allen entering his third year as a starter along with the additional talent of Stefon Diggs and Zack Moss. They know more points on the board for their offense means more advantageous pass rushing situations for them.

"We're going to go rush the passer, and I want to get some sacks this year I know the rest of the guys want to get some sacks," said Harrison Phillips. "And so I think that's the perfect combination of how we can be a successful team and really make a run here is our offense go out, strike first, strike early get a good a good lead for us, and then let the dogs that we have on our defense get after the quarterback and let us go eat."

"I'm excited for all of us to get out on the field because I know we're all going to be out there, relentlessly hunting that quarterback trying to make plays and just keep pushing each other," said Hughes. "I think when you have that level of competition in your room. It makes the room, it makes the year, really fun."

Fun for everyone but opposing offenses.