NFL Nation assesses the breakout first-year players on each team.

AFC EAST

This one is easy: The Bills had a potential NFL defensive rookie of the year candidate in CB Ronald Darby until the second-round pick from Florida State had a few hiccups in coverage over the final month of the season. Kansas City's Marcus Peters is the overwhelming favorite to land that award, but Darby was still among the NFL's best rookies this season and he'll enter 2016 as an undisputed starter in a Bills defense that is expected to undergo changes up front. -- Mike Rodak

Miami didn't get a ton of production from its rookie class, but first-round pick DeVante Parker's late-season push was impressive. Parker replaced injured starter Rishard Matthews and had 22 of his catches for 445 yards in his last six games. He finished the season with a 19.4 yards-per-catch average and three touchdowns. -- James Walker

The Patriots received significant contributions from the rookie class. Guards Shaq Mason (66 percent of the snaps) and Tre' Jackson (54.2 percent) -- both fourth-round picks -- were part of a three-man rotation. Meanwhile, long snapper Joe Cardona (fifth round, Navy) handled his job well, undrafted center David Andrews started the first 10 games of the season and helped bail the team out when a string of injuries hit, and undrafted Brandon King was second on the team with 12 special teams tackles. But we'll give the nod to Malcom Brown, who played 46.5 percent of the defensive snaps as the top option in a committee to replace departed Vince Wilfork at defensive tackle. -- Mike Reiss

A no-brainer: Defensive end Leonard Williams was the Jets' best rookie. He was an important contributor from Day 1, and wound up playing 77 percent of the defensive snaps. Williams, drafted sixth overall, was terrific against the run. He needs to improve as an interior pass rusher, as he finished with only three sacks. -- Rich Cimini

AFC NORTH

Running back Buck Allen was the most productive rookie for the Ravens, and it wasn't even close. His ability to turn short catches into big plays carried the Baltimore offense at times. Over the last seven games (after Justin Forsett broke his arm), the fourth-round pick totaled 627 yards and scored three touchdowns. Only Arizona's David Johnson had more yards among rookies during that span. The Ravens hope to get more out of this draft class next season, when wide receiver Breshad Perriman returns from injury and tight end Maxx Williams adds more bulk in the offseason. -- Jamison Hensley

It's hard to name one specific player since the Bengals didn't give many of their rookies extended playing time, as expected. That's the function of a deep veteran roster. That said, tight end Tyler Kroft had the most productive year of the Bengals' first-year players. He caught 11 passes (on 14 targets) for 129 yards and a touchdown. He filled in admirably down the stretch when touchdown-magnet Tyler Eifert missed three of the last five games with head and neck injuries. Offensive tackles Cedric Ogbuehi and Jake Fisher also proved to be competent backups. Ogbuehi could be Cincinnati's starting right tackle in 2016. -- Coley Harvey

DT Danny Shelton did not make a large impact immediately, but he did improve as the season went on. The 12th overall pick from 2015 had to learn how to play in the NFL, and as he developed, he started making more of an impact. Shelton's work ethic bodes well for his future, though he does need to work on his conditioning. -- Pat McManamon

Linebacker Bud Dupree didn't have much competition here -- he was the only rookie playing significant snaps for Pittsburgh. Dupree earned a starting role late in the year and was disruptive in two playoff games with a tackle for a loss in each. He didn't record a sack in his final 10 NFL games and admitted to hitting a rookie wall physically. He finished with a respectable 26 tackles and four sacks despite sharing reps with Arthur Moats as part of a four-man outside linebacker rotation. The Steelers are grooming Dupree to be their next great linebacker off the edge, and he seems eager to oblige despite a few bumps along the way. -- Jeremy Fowler

AFC SOUTH

Although first-round pick Kevin Johnson experienced some growing pains, the rookie cornerback got a lot of important experience and showed he will be a valuable asset for the franchise. The Texans had one of their more productive rookie classes as a group this season. Second-round LB Benardrick McKinney became a starter by the end of the season and third-round WR Jaelen Strong showed he could contribute. -- Tania Ganguli

Receiver Phillip Dorsett drew all the headlines because he was the Colts' first-round pick, but nose tackle David Parry was the most consistent player of the team's entire rookie class. Parry, who was selected in the fifth round, entrenched himself on the defensive line possibly for years to come by starting every game last season. He finished with 31 tackles and a sack. -- Mike Wells

It's a hard choice between G A.J. Cann, whom the team said didn't allow a sack, and WR/PR Rashad Greene, but I'll go with Greene. He turned two games around for the Jaguars with big punt returns -- a 63-yarder that set up the Jaguars' go-ahead touchdown against Tennessee and a 73-yarder for a TD to break open a close game against Indianapolis. Greene played in only nine games because he missed seven on IR/designated to return with ligament damage in his thumb. He averaged 16.7 yards on 18 punt returns, which would have led the league by more than 4 yards per return if he had enough returns to qualify. -- Mike DiRocco

Quarterback Marcus Mariota was easily the Titans' best rookie in 2015. His performance in 12 games established that Tennessee has an answer at the hardest position to fill. Now they need to surround him with talent, protect him and create a scheme that can work. -- Paul Kuharsky

AFC WEST

If left tackle Ty Sambrailo, who suffered a season-ending shoulder injury in Week 3, had not ended up on injured reserve he was headed to the best season among the team's rookies. That said, guard Max Garcia and outside linebacker Shane Ray each played significant time on a playoff team. Ray played 31 percent of the snaps in the regular season for the league's No. 1 defense and finished with four sacks and 20 tackles, behind two Pro Bowl selections at the position in Von Miller and DeMarcus Ware. But in the end, just because of his workload and responsibility, Garcia probably gets the nod, as he played 48.9 percent of the team's offensive snaps. The Broncos will be looking for him to be a full-time starter next season if he can iron out some inconsistencies in pass protection. -- Jeff Legwold

Marcus Peters was picked on by opposing quarterbacks more than any other cornerback in the league, and he allowed some touchdowns. But the first-round draft pick made his share of plays, snagging eight interceptions in the regular season and another in the playoffs. He helped transform a defense that struggled to force turnovers in 2014 to one that was fourth in the NFL in takeaways. -- Adam Teicher

No. 4 overall pick Amari Cooper did not disappoint. His 72 catches, 1,070 receiving yards and led NFL rookies, while his six touchdown catches tied for tops in the league among first-year players. Yes, it was the most productive season by a rookie receiver in franchise history, a list that includes the likes of Hall of Famer Fred Biletnikoff and Cliff Branch. And Cooper became the first Raiders WR with a 1,000-yard receiving season since Randy Moss in 2005. -- Paul Gutierrez

Former MLS goalkeeper Josh Lambo, an undrafted rookie out of Texas A&M, finished second among rookie kickers in 2015 with 106 points. Lambo was 26-of-32 (81.3 percent) on field goals for the Chargers, with a long of 54 yards. That kick would have sealed a win over the Steelers in Week 6 had San Diego's defense kept Le'Veon Bell out of the end zone. Lambo made seven of his eight field goals in the fourth quarter. His one issue? He missed four extra points from the new 33-yard distance. -- Eric D. Williams

NFC EAST

Randy Gregory (second-rounder) and La'el Collins (undrafted) both arrived in Dallas under the microscope after falling in the draft due to off-the-field issues. But it was first-rounder Byron Jones who had the best season of the bunch. Quietly, by season's end, an argument could be made that Jones was the team's best defensive back even if he did not have an interception. He showed incredible versatility by playing four different spots: outside corner, slot corner, dime and free safety. The Cowboys seemed to settle on where he will be best in the future by playing him at safety. -- Todd Archer

The only two draft picks who made any real contribution were tackle Ereck Flowers and safety Landon Collins, who started 15 and 16 games, respectively. The problem is, they both had major struggles, since each was asked to do more than he was ready to do. Flowers isn't an NFL-caliber pass protector yet, but he had to play left tackle because the Giants had no one else. Collins is a liability in coverage, but he had to play some free safety because they had no one else. Flowers is strong in the run game and Collins is good against the run, but their rookie seasons had more downs than ups. So I'll give this one to undrafted tight end Will Tye, who took over as the starter in November due to injury problems at that position and ended up fourth on the team in both catches (42) and receiving yards (464). -- Dan Graziano

There are two arguments for third-round linebacker Jordan Hicks being the best player the Eagles drafted in 2015. The first is what Hicks did in the five games he started after injuries forced the Eagles to play him: a sack, two interceptions and three fumble recoveries. The second is what happened to the defense after Hicks was placed on injured reserve with a torn pectoral tendon. The Eagles lost their next three games, giving up 45 points to Tampa Bay and 45 more to Detroit, and missed the playoffs. First-round pick Nelson Agholor was not a factor. Second rounder Eric Rowe showed promise late in the season at cornerback. But Hicks made an impact. -- Phil Sheridan

The Redskins produced one of their best rookie classes in some time, with multiple players contributing. The fifth overall pick, Brandon Scherff, was a Day 1 starter, though he was switched from tackle (where he struggled) to guard (where he improved). Second-rounder Preston Smith finished strong with eight sacks and his development bodes well for the future, but he was inconsistent. So, perhaps, the best overall rookie -- in part because of where he was picked and what he did -- was Jamison Crowder. The fourth-round pick produced 59 catches and two touchdowns as the No. 1 slot receiver, giving the Redskins passing game a boost when DeSean Jackson missed most of seven games because of injuries. -- John Keim

NFC NORTH

Several Bears' rookies made meaningful contributions in 2015, but running back Jeremy Langford had the most overall impact with 816 all-purpose yards and seven touchdowns. Langford is one of six rookies in franchise history with at least six rushing touchdowns and one receiving touchdown. His 83-yard touchdown catch in St. Louis on Nov. 15 is the fourth longest reception by a RB in Bears history. Langford also joined Hall of Famers Walter Payton and Gale Sayers as the only players in team history with 100 receiving yards, one rushing touchdown and one receiving touchdown in a single game. Not bad for a fourth-round pick. -- Jeff Dickerson

This is a tough one, because RB Ameer Abdullah had a pretty good year. But based on draft position and expectations, CB Quandre Diggs was the best rookie the Lions had this season. Diggs came into the spring and took No. 1 reps almost immediately. He was worked into the lineup during the season opener and took over the nickel role after a season-ending injury to Josh Wilson. He finished the season with 35 tackles, a forced fumble and a fumble recovery. He also solidified himself as a player who should be the team's nickel corner in 2016 and potentially beyond. There is improvement that needs to happen, but overall, Diggs was a gem of a pick at selection No. 200. -- Michael Rothstein

General manager Ted Thompson hit on his first-round pick for the second year in a row. Much like safety Ha Ha Clinton-Dix did last season, cornerback Damarious Randall became a starter early in his rookie year and looks like a long-term starter. Randall showed the kind of ball skills that led the Packers to take him at No. 30 overall, as he tied for the team lead with three interceptions. Yes, he blew the coverage on Cardinals receiver Larry Fitzgerald on the first play of overtime in Saturday's playoff loss, but it shouldn't change the fact that he was the Packers' best rookie this season. -- Rob Demovsky

The Vikings got impressive contributions across their rookie class -- linebacker Eric Kendricks, defensive end Danielle Hunter and wide receiver Stefon Diggs all made the Pro Football Writers of America's All-Rookie team -- but Kendricks sticks out from the group for his ability to jump into the Vikings' middle linebacker position after the bye week. He led the team in tackles, posted four sacks and became a solid every-down player in a defense that asks a lot of its linebackers. -- Ben Goessling

NFC SOUTH

Although first-round draft pick Vic Beasley Jr. set a franchise rookie record with a team-leading four sacks, expectations were much higher for the pass-rusher who dealt with a torn labrum in his right shoulder. That's why we'll give the top rookie nod to defensive lineman Grady Jarrett, the fifth-round draft pick who played college ball with Beasley at Clemson. Jarrett made the most of his 255 snaps, posting 24 tackles, four tackles for losses, a sack and two quarterback hits. And Jarrett showed versatility in playing multiple positions along the D-line. -- Vaughn McClure

It's pretty close between linebacker Shaq Thompson and wide receiver Devin Funchess, although neither had what you would call a huge year. The edge goes to Funchess, who caught 31 passes for 473 yards and five touchdowns. He didn't replace 2014 first-round pick Kelvin Benjamin, who suffered a season-ending knee injury in training camp. But he showed glimpses of the potential in this offense, and the team is looking forward to seeing what he can do next season when he plays with Benjamin. -- David Newton

The Saints' second of two first-round draft picks, Stephone Anthony, stepped right into a starting role as the middle linebacker and signal-caller for New Orleans' defense. He played nearly every snap all season and tied for 20th in the NFL with 112 tackles. The Saints credited Anthony with 142 tackles by their own accounting, which broke Hall of Famer Rickey Jackson's rookie franchise record. Anthony also had a sack, an interception and two forced fumbles. The 6-foot-2, 245-pounder still went through some growing pains, especially in pass coverage. But his poise and athleticism stood out, and he should be a building block going forward for a defense that needs as many as it can get. -- Mike Triplett

QB Jameis Winston threw for 4,042 yards and 22 touchdowns with 15 interceptions in 2015, making him just the third rookie quarterback to surpass 4,000 yards. The other two? Cam Newton and Andrew Luck. The Bucs' offense finished fifth overall -- fifth in rushing and 17th in passing -- despite being led by a rookie. Winston should be named the league's Rookie of the Year. -- Mike DiRocco

NFC WEST

Running back David Johnson was already a dynamic three-way threat before he took over for the injured Chris Johnson after Week 12. For the season, he posted 1,636 all-purpose yards and a franchise rookie record of 13 touchdowns. -- Josh Weinfuss

With a tip of the cap to right tackle Rob Havenstein for a solid rookie campaign, there's not much of a debate here. Running back Todd Gurley is a frontrunner for the NFL's Offensive Rookie of the Year award after he finished third in the NFL in rushing (1,106 yards) despite playing in only 13 games and starting just 12. Give Gurley some stability on the offensive line and a passing game that can keep defenses from loading the box, and you have all the makings of the type of RB who can carry a team on his back. -- Nick Wagoner

Jaquiski Tartt was a relative unknown as the Niners' second-round draft pick out of Samford, but the strong safety made his presence felt immediately with his hard-hitting style. And after taking over the starter's role when veteran Antoine Bethea was lost for the season with a shoulder/chest injury in Week 10, Tartt sacked Jay Cutler, intercepted Johnny Manziel. He finished the season with 65 tackles. -- Paul Gutierrez

The Seahawks drafted Tyler Lockett expecting a dynamic returner who could eventually develop into a wide receiver. What they discovered was he was already a pretty good pass-catcher. Lockett's 664 receiving yards ranked third among rookies, and his six touchdowns were tied for first. Despite being only 5-foot-10, Lockett showed he can beat press coverage on the outside and make tough catches. He was an All-Pro on special teams, scoring as both a kickoff returner and a punt returner. On top of the production, Pete Carroll called Lockett the hardest-working player on the team at one point during the season. Not a bad debut for someone who lasted until the third round. -- Sheil Kapadia