Coaches, rookies, front-office execs, free-agent signings and more: NFL Nation covers the single most important offseason addition for every team.

AFC East | AFC North| AFC South | AFC West

NFC East | NFC North | NFC South | NFC West

AFC EAST

Coach Sean McDermott

Time will tell if McDermott is the best pickup for the Bills this offseason, but there is no doubting he was the most important addition to the organization. Owners Terry and Kim Pegula have seemingly consolidated the power of their football operations under McDermott, whose strong standing within the organization was evident in the Pegulas' decision to fire general manager Doug Whaley after the draft. The Bills' marketing slogan for the 2017 season will be, "It starts with one," and they have made it clear that McDermott is that one leader. -- Mike Rodak

MLB Lawrence Timmons

Signing Timmons in free agency wasn't a huge splash, but those who watched Miami's atrocious run defense (30th in the NFL) know he was a key pickup. The 10-year veteran adds a much-needed physical presence in the middle of the Dolphins' defense. -- James Walker

WR Brandin Cooks

Acquired from the New Orleans Saints along with a fourth-round pick in exchange for first- and third-round selections, Cooks brings youth (he's 23), speed, the ability to beat man coverage, and dynamic playmaking ability to a Tom Brady-led offense that showed some deficiencies in the first half of Super Bowl LI. Owner Robert Kraft is on record as saying Cooks is the only receiver the team has acquired in his tenure with the potential to make as big of an impact was Randy Moss. -- Mike Reiss

S Jamal Adams

After a low-budget approach to free agency, the Jets needed to hit a home run in the draft -- and they did. Not only will Adams help shore up a weak position, but his strong intangibles will improve the locker room culture. His reputation preceded him. When team officials gave him a tour of the facility the day after the draft, staffers emerged from their offices and applauded. -- Rich Cimini

AFC NORTH

Senior offensive assistant Greg Roman

Roman's challenge is to get the Ravens' slumping running game on track. In his past five full seasons as an offensive coordinator, his teams ranked in the top five in rushing four times. How important is the running game to Baltimore? When the Ravens gain over 100 yards rushing, their record is 60-22 (.732), the sixth-best mark over that span. -- Jamison Hensley

WR John Ross

There's a big question as to whether Ross will be healthy enough to contribute early, but for an offense that lacked speed on offense, Ross' 4.22 40-yard dash speed could open things up enough that A.J. Green is no longer drawing so much coverage by himself. That could go a long way to patching up the Bengals' offense this season. -- Katherine Terrell

DE Myles Garrett

The draft's first overall pick steps in to a defense that suddenly includes LB Jamie Collins and improving DT Danny Shelton and LB Christian Kirksey. That group give Gregg Williams plenty of talent to work with as the Browns build a defense. -- Pat McManamon

DE Tyson Alualu

This understated value acquisition will pay off for Pittsburgh in the 2017 season. Once a top-10 pick, the Steelers signed Alualu at $3 million per year as a swing lineman to help starters Cameron Heyward, Javon Hargrave and Stephon Tuitt. Alualu has started 87 games in his career, so his presence essentially gives Pittsburgh a fourth starter and eliminated the need to draft defensive line help last month. Draft picks T.J. Watt and JuJu Smith-Schuster should prove capable, but with a depth chart mostly cemented, Alualu provides the most immediate help for a team ready to win now. -- Jeremy Fowler

AFC SOUTH

QB Deshaun Watson

The first-round pick might not start in 2017, but the Texans hope he is their quarterback of the future and can end their franchise-long quarterback carousel. Unless Watson blows the Texans away during training camp -- or starter Tom Savage struggles early -- expect Watson to spend most of his rookie season on the bench. But, even if he doesn't play this season, Houston has high hopes he will be ready for 2018. -- Sarah Barshop

General manager Chris Ballard

Owner Jim Irsay finally sealed the divorce between GM Ryan Grigson and coach Chuck Pagano when he fired Grigson in January. Ballard has put an emphasis on defense to try to give quarterback Andrew Luck and the offense help this offseason. Ballard has acquired 13 new defensive players in the draft and free agency to help improve a unit that was 30th in the NFL last season. -- Mike Wells

Executive vice president of football operations Tom Coughlin

After winning only 17 games over the past five years, the Jaguars needed to move in a new direction, and owner Shad Khan turned to the man who originally built the franchise into one of the AFC's best in the mid- to late '90s. Coughlin has injected some much-needed discipline and accountability into the franchise, and several players have said publicly that the locker room needed the changes. Winning is now the only thing that matters. Previous coach Gus Bradley's philosophy was that players should strive to be their best and the victories would come if that happened. -- Mike DiRocco

CB Logan Ryan

Ryan has been part of two Super Bowl-winning teams in New England, so he knows what it takes to win at the highest level. He's an outspoken leader who might blossom in an environment where there is more room for that. And he should work against the bigger receivers the Titans face, while first-round pick Adoree' Jackson works against the smaller, faster types. -- Paul Kuharsky

AFC WEST

G Ronald Leary

Sure, an interior offensive lineman is not always cause for confetti -- there are many personnel executives in the league who believe a team should never use a first-round draft pick on a guard. But there's a reason the Broncos paid top dollar for Leary: They need direction up front, they need some additional leadership and, after three years of trying to find the combination, they need stability. -- Jeff Legwold

QB Patrick Mahomes II

The Chiefs have been held back more often than not since their Super Bowl victory 47 years ago by their limitations at quarterback. That's why they made the bold trade to move up and draft Mahomes in the first round. He's their first serious attempt in decades at solving the long-term quarterback problem, and how he fares will eventually determine the fate of the franchise. He won't play much, if at all, as a rookie, but he'll carry some heavy expectations starting in 2018. -- Adam Teicher

Coach Anthony Lynn

After finishing 9-23 over the past two seasons, the Chargers needed an infusion of new energy at Chargers Park. And Lynn's no-nonsense approach has gone over well with both players and the front office. The team is also hoping Lynn's hiring of strength coach John Lott will curb the rash of injuries this team has experienced over the past two seasons. -- Eric D. Williams

RB Marshawn Lynch

Sure, acquiring Oakland's favorite football-playing son serves as an olive branch, of sorts, to East Bay fans upset over the team's pending move to Las Vegas. And even Raiders coach Jack Del Rio wonders how much the erstwhile Beast Mode has left in his tank. But this much is true: Even if the tank is three-fourths full after a year off in retirement, Lynch adds some much-needed physicality to a running game that was already the No. 6-ranked attack last season. The ultimate goal in Oakland with Lynch? Give him the ball on the 1-yard line with time running out in the Super Bowl. Too soon, Seattle? -- Paul Gutierrez

NFC EAST

Cap space

The Cowboys did not make any splashy free-agent additions, although keeping wide receiver Terrance Williams was a surprise. The biggest acquisition of the offseason will come June 2, when they add $14 million in cap space with Tony Romo's release becoming official. Romo will count $8.9 million against the cap next season, but that is a pittance compared to the $25.2 million he was scheduled to count. With Dak Prescott on his rookie deal through 2019, the Cowboys will have a flexibility they did not have because of Romo's prodigious cap figures. Don't expect the Cowboys to immediately shell out for free agents, though. They'll save the cap space for the future to avoid restructuring as many contracts as they have done over the past few years. -- Todd Archer

WR Brandon Marshall

Marshall will make the biggest impact of all the Giants' newcomers this season, specifically with his red zone presence. The only wide receiver with more red zone touchdowns than Marshall's 19 the past three seasons is Antonio Brown. That will open things up for Odell Beckham Jr. and for the running game, where Marshall will also be an asset as a high-end blocker from the receiver position. Marshall will lead to more points for the Giants; they ranked 26th in the NFL last season at just 19.4 points per game. -- Jordan Raanan

WR Alshon Jeffery

Per ESPN Stats & Information, Eagles receivers dropped a league-high 5.8 percent of their targets and finished second-to-last in receiving yards (1,849). Jeffery, when healthy, gives QB Carson Wentz a legitimate No. 1 wideout. "He's exciting to watch," head coach Doug Pederson said. "He's a big target, obviously, and we've just got to get him and Carson continuing to stay on the same page as we go throughout the whole offseason." -- Tim McManus

Defensive line coach Jim Tomsula

The Redskins needed to fix the line and wanted to improve their defense, which led to Greg Manusky's being promoted to coordinator. But if the line doesn't improve, the defense won't and that's where Tomsula comes in. The Redskins probably will have three new starters up front, including first-round pick Jonathan Allen. The energetic Tomsula earned a strong reputation as a line coach in San Francisco before a one-year stint as head coach. Now he must incorporate new starters and develop depth with some inexperienced reserves. Tomsula will have a big say in the overall defensive growth. -- John Keim

NFC NORTH

QB Mitchell Trubisky

There's not even a close second. Trubisky was drafted second overall to be Chicago's quarterback of the future. The city hasn't had a true franchise quarterback since Sid Luckman in the 1940s, so to say the fan base is anxious is an understatement. If Trubisky develops into the quarterback GM Ryan Pace envisions, the Bears probably will end their long playoff drought in the not-so-distant future. If Trubisky doesn't pan out, the Bears better hope Mike Glennon is the real deal; otherwise they'll remain stuck in the football abyss. -- Jeff Dickerson

RT Rick Wagner

The Lions were quick to target Wagner in free agency, and they landed him for a premium among right tackles. Detroit struggled to run the ball and protect Matthew Stafford consistently last season. The team thinks the addition of Wagner and right guard T.J. Lang will go a long way toward fixing their woes up front. -- Michael Rothstein

TE Martellus Bennett

This could be one of the biggest-impact acquisitions in the NFL. Bennett should give Aaron Rodgers what he had last year in Jared Cook and more. Unlike Cook, who had never made the playoffs before he came to Green Bay, Bennett comes to the Packers after winning the Super Bowl with the Patriots. At 6-foot-6, Bennett is a gigantic, athletic target for Rodgers. The addition of another veteran tight end, Lance Kendricks, should make the Packers' double-tight-end sets difficult to defend. -- Rob Demovsky

RB Latavius Murray

The Vikings needed a running back they could trust to carry the ball, catch it out of the backfield and protect Sam Bradford. And they wanted one who wouldn't break the bank after years of Adrian Peterson's being the highest-paid back in the league. Murray doesn't have Peterson's dynamism, but he's a versatile fit for the Vikings' offense and it was a low-risk bet for the team. If he doesn't work out, the Vikings can get out of Murray's contract with just $1.2 million in dead money after this season. -- Ben Goessling

NFC SOUTH

DT Dontari Poe

The two-time Pro Bowler sounded relieved to play in a system that is likely to showcase his complete defensive skill set more so than the scheme in Kansas City. Coach Dan Quinn already said he planned to use Poe both at nose tackle and the 3-technique, and Poe has untapped pass-rush ability that Quinn certainly will help unleash. Now the question is, will Poe also be the Falcons' goal-line back on offense? -- Vaughn McClure

RB Christian McCaffrey

There was a temptation to go with Captain Munnerlyn, signed in free agency to fill a key role as the nickel back. He also can play outside in a crunch, so this solidifies the secondary. But there's no denying that McCaffrey, the do-it-all running back out of Stanford who was selected No. 8 in the draft, was the biggest acquisition. It's like getting four players in one with his ability to play running back, slot receiver and wide receiver and return punts. He's unlike any weapon Cam Newton has had since arriving in 2011. -- David Newton

CB Marshon Lattimore

I don't want to lump too many expectations on the rookie right away -- especially after he played only one full year at Ohio State. But Lattimore's falling to the No. 11 pick in the draft was the Saints' biggest "win" of the offseason after they considered much pricier options at cornerback over the past year (Josh Norman last summer and Malcolm Butler this spring). The Saints' most expensive new addition was free-agent guard Larry Warford, and their most high-profile newcomer is running back Adrian Peterson -- both of whom could make an earlier impact. But Lattimore has the best chance to be a long-term game-changer. -- Mike Triplett

WR DeSean Jackson

Jackson will stretch the field, giving the Bucs speed they've lacked since Joey Galloway departed and more explosive-play opportunities. The Bucs averaged just 4.03 yards after the catch last season, 31st in the league. Jackson has gained 2,861 yards after the catch since 2008, ninth-most among WRs during that span. The Bucs were also the only team in the NFL without a 50-yard pass play last season, according to Elias. Jackson leads active NFL receivers with the most 50-yard catches (37), per ESPN Stats & Information. -- Jenna Laine

NFC WEST

K Phil Dawson

The Cardinals lost three games last season at the foot of their former kicker, Chandler Catanzaro. Arizona replaced him with Dawson, who has been consistent throughout his 19-year career. Having a kicker with experience making big kicks could be the difference between Arizona going to the playoffs and sitting at home. -- Josh Weinfuss

Coach Sean McVay

McVay is only 31, the youngest head coach in modern NFL history, but a significant amount of people believe he is a star in the making. McVay is exceedingly energetic and positive, a natural leader with a magnetic personality who is something of a prodigy when it comes to the way offenses work. The Rams, organizationally, needed a jolt. And they needed someone who could finally make something of an offense that finished last in the NFL in yards each of the past two years and among the league's worst for much longer than that. McVay has already assembled what appears to be a very good coaching staff. And he should do wonders for second-year quarterback Jared Goff, the No. 1 overall pick in 2016. -- Alden Gonzalez

Coach Kyle Shanahan

Shanahan was widely regarded as the top coaching candidate available, and his offensive acumen should help turn around an offense that has been stagnant for the past few years. Shanahan's relationship with GM John Lynch is off to a great start, and they seem to be on the same page with what it takes to rebuild the Niners. While San Francisco also added some key pieces in terms of players, nobody is more important to the future of the franchise than Shanahan. -- Nick Wagoner

RB Eddie Lacy

In both 2015 and 2016, the Seahawks were left scrambling at times because of injuries at running back. Lacy is on a one-year deal and should receive a nice paycheck -- either from the Seahawks or another team -- if he turns in an impressive 2017 campaign. He has the bruising style Pete Carroll likes and has averaged 2.15 yards after contact since entering the NFL, sixth-best among running backs. Seattle's offense is at its best when the run game is clicking. With Lacy, Thomas Rawls and C.J. Prosise, the Seahawks have given themselves multiple options for 2017. -- Sheil Kapadia