Buffalo Bills' 2020 NFL free-agent signings: Mario Addison among additions to defense

NFL free agency is off and running, and we're keeping track of every major signing, trade and release of the 2020 offseason, with analysis from our NFL Nation reporters and grades from Bill Barnwell. The new league year began March 18, which means free-agent signings can be made official after that. The first round of the 2020 NFL draft begins April 23.

Here's a breakdown of every 2020 NFL free-agent signing by the Buffalo Bills, and how each will impact the upcoming season:

E.J. Gaines, cornerback

What it means: Gaines adds depth and versatility to the Bills' cornerbacks room. They were hurting for outside corners behind Tre'Davious White, Josh Norman and Levi Wallace; when healthy, Gaines provides some stability as well as comfort with Buffalo's defensive scheme.

What's the risk: Gaines is an injury risk after missing all of last season and most of the 2018 season. He was an 11-game starter for the Bills in 2017, however, and his familiarity with Leslie Frazier's defense should help accelerate his acclimation whenever teams can return to the practice field.

Vernon Butler, defensive tackle

What it means: Butler adds depth at defensive tackle and provides spark as a pass rusher. Playing next to Ed Oliver, Butler could tap into the potential that led the Panthers to draft him No. 30 overall in 2016.

What's the risk: Butler nearly flamed out completely in his first three seasons with the Panthers before breaking out for six sacks last season. Brandon Beane is paying more for potential than prior production here, with an average of $8 million per year over the next two seasons. If he captures his first-round ceiling and builds off his career year, this is a steal and potentially leads a dynamic duo in the making with Oliver. If not, it’s a deal Buffalo can quickly wash its hands of.

Mario Addison, defensive end

What it means: Buffalo had a noticeable hole at defensive end after losing Shaq Lawson to the Dolphins and immediately filled it with Addison. His familiarity with Brandon Beane, Sean McDermott and defensive line coach Eric Washington should make this a seamless transition on the field. His 9.5 sacks in 2019 would have tied for the team lead in Buffalo last season.

What's the risk: A three-year contract for a 33-year-old edge rusher is certainly a risk, but Beane is banking on Addison's experience playing under McDermott and Washington. It is by no means a long-term fix and defensive end still remains a position of need for the Bills in the near future.

A.J. Klein, linebacker

Length of deal: 3 years, $18 million

What it means: The Bills get a smart linebacker to presumably replace the recently-retired Lorenzo Alexander. While he probably won't push for an All-Pro selection, Klein is reliable, he understands the system given his familiarity with Sean McDermott and is a good "locker room guy." It's not splashy, but that's generally not Buffalo's M.O.

What's the risk: In typical Buffalo fashion, this is a low-risk move. It's low-ceiling as well but Brandon Beane opted for familiarity over fireworks. Klein might take snaps away from 2019 rookies Vosean Joseph and Tyrel Dodson -- neither of whom saw the field last season but were poised to battle for the strongside linebacker position this offseason. But the Bills' moves on the first day of legal tampering showed the league they believe their Super bowl window is now; they're not interested in risking that window on the unknown.

Quinton Jefferson, defensive tackle

The Bills agreed to terms on a two-year deal with the defensive tackle, he told ESPN's Josina Anderson.

What it means: Jefferson adds experience, depth and versatility to the Bills' defensive line. A 12-game starter in each of the past two seasons, he can play both defensive tackle and defensive end. That should come in handy for Buffalo, which could use the depth at both positions.

What's the risk: Jefferson has been productive over the past two years but won't be relied on to set the tone for the defensive line. He should find himself in a reduced Jordan Phillips role behind Ed Oliver, but with just two year deal, it wouldn’t be the end of the world if he didn’t pan out and Oliver had to play more snaps.

Josh Norman, cornerback

The Bills have agreed to a one-year deal with Norman worth $6 million with incentives that can reach $8 million.

What it means: Norman presumably comes to Buffalo to be the starting corner opposite Tre'Davious White. It means Norman will have an opportunity to play a role other than "de facto top cornerback" for the first time since 2014 -- which could ultimately do the veteran some good. On a grand scale, Buffalo beat out three other interested parties because of its talent on defense and its readiness to compete, which is a testament to how the perception of the Bills has changed.

What's the risk: The terms on the deal at $6 million is not a drop in the bucket, but it's not the worst investment for a one-year deal. At best, Norman flirts with his All-Pro form from 2015 and makes an already stout Buffalo pass defense even more difficult to throw against. If Norman flames out, the Bills are on the hook for one season and have last season's starter, Levi Wallace, available.

Quinton Spain, guard

The Bills agreed to a three-year, $15 million contract with Spain.

What it means: It means the Bills will return all five of their starting offensive linemen from the 2019 season. Spain, a former undrafted free agent, was the most reliable lineman on the field last season, playing 16 games and committing the fewest penalties out of any of Buffalo's starters -- all without allowing a single sack. It also means, however, that the team will commit to Cody Ford at right tackle despite considering a move to guard.

What's the risk: Three years is a commitment, but $15 million over that span is a bargain -- and a low-risk move -- for a player as consistent as Spain. He has played at least 14 games in four of his five NFL seasons and is rarely penalized. He is 28 and in the prime of his career.

Jason Croom, tight end

The Bills have re-signed Croom to a one-year contract.

What it means: Since Croom was an exclusive-rights free agent, his return was all but inevitable. It means the Bills believe in him enough, despite missing all of the 2019 season, to let him compete for a roster spot again this offseason.

What's the risk: It's a low-risk deal given the length -- basically no risk. Dawson Knox should be entrenched as the starter unless he takes a massive step backward. Tommy Sweeney and Tyler Kroft should see a share of snaps behind Knox, while Lee Smith operates as the blocking tight end.

Tyler Matakevich, linebacker

The Bills agreed to a two-year, $9 million contract with the veteran special teamer.

What it means: The Bills look to shore up their special teams unit with one of the league's unheralded stars in that phase of the game. He led the league with 16 special teams tackles last season and will provide consistency and depth for a roster looking to contend. He also played college football with Bills left tackle Dion Dawkins at Temple.

What's the risk: It likely spells the end of Julian Stanford's time in Buffalo, but other than that it's a typical low-risk move by the Bills. The $9 million Buffalo will pay him over the next two years is a steep figure for a specialist, but the team has plenty of money to work with.

Taiwan Jones, running back

The Bills agreed to a one-year contract with the veteran special teamer.

What it means: Seeing that Jones had all of nine rushing attempts in 2019, Buffalo isn't bringing him back as a complement to Devin Singletary. Rather, he'll earn his reps on special teams -- where he's played extensively in seven of his nine NFL seasons. It's another familiar name as well; Jones spent the 2017 and 2018 seasons with the Bills before moving on to Houston last season.

What's the risk: Little to none -- he won't be relied on to spell Singletary and can focus on making as big of an impact as possible on special teams. Jones has rarely played a full season, logging 16 games just once since entering the league in 2011. But on a one-year deal, it's a relationship that can dissolve easily if it proves to be unfruitful.

Daryl Williams, offensive lineman

What it means: Williams will initially serve as a veteran depth piece at guard and tackle. It likely means swing tackle LaAdrian Waddle won't return to the Bills in 2020. Williams' addition gives Buffalo at least three backups who can play multiple positions, along with its five starting offensive linemen from 2019.

What's the risk: Williams was considered one of the top young tackles in the league before suffering a knee injury prior to the 2018 season. He returned in 2019, but played at a level far below what he showed in 2017. A one-year deal implies little risk, but the reward could be huge if Williams regains his form.