The 2018 iteration of the NFL's free agency period had it's fair share of excitement and movement as some of the league's top players at their respective positions have switched teams, and even sides of the country. From interior players like Ndamukong Suh and Andrew Norwell to signal-callers in Sam Bradford and Case Keenum, we break down one PFF signature stat to know for every team's top-graded new signing to date.

AFC East

RB Chris Ivory

2017 Grade: 50.4

Ivory played sparingly in 2017, but he still managed to produce and he ended the year ranked 37th among 53 backs (just one spot behind former teammate Leonard Fournette) with an average of 2.47 yards after contact per carry. More importantly though, Ivory displayed the ability to contribute on passing downs, something that wasn't a major part of his game in seasons past. All told, on average he forced a missed tackle every 2.1 receptions, which was the highest rate among backs with at least 10 targets, and his receiving grade of 76.6 would have been good for 22nd among players at the position, if he had played enough snaps to qualify for a rank.

G Josh Sitton

2017 Grade: 86.0

In his 10 professional seasons, Sitton has been as consistent as they come and is the only guard in PFF history to grade above 85.0 in nine consecutive seasons, with the next-best mark sitting at five consecutive seasons. Arguably the best pass-protecting guard in the game, Sitton has allowed just 18 pressures in the last two seasons, and his average of 44.5 pass-blocking snaps played per pressure allowed is the best rate among the 43 guards with at least 750 pass-blocking snaps in that span.

Edge Adrian Clayborn

2017 Grade: 85.5

Clayborn ended the 2017 campaign with 54 total quarterback pressures and a pass-rush productivity of 10.9, which were good for 16th and 10th, respectively, among 68 4-3 defensive ends with at least 135 pass-rushing snaps. Clayborn’s career year was highlighted by a tremendous single-game performance against the Dallas Cowboys, where he racked up a colossal 12 quarterback pressures and ended the game with a pass-rushing productivity of 28.8 – the highest single-game mark of the season by an edge defender.

LB Avery Williamson

2017 Grade: 85.6

Since 2015, Williamson has been productive in all facets of the game and has racked up 98 run stops, the third-most among inside linebackers in that span. In coverage, he has allowed a reception once every 12.6 coverage snaps, which is the fourth-best mark among linebackers with at least 75 targets in that span.

AFC North

WR Michael Crabtree

2017 Grade: 71.4

During his 2017 with the Raiders, Crabtree developed a knack for putting together his best performances in crunch time and generated a passer rating of 105.2 from his fourth quarter/overtime targets – the fifth-best mark among receivers with at least 30 targets.

LB Preston Brown

2017 Grade: 71.6

Brown’s best plays of the season came against the run last year and he ended the season with 31 run stops, the 11th-most among inside linebackers.

2017 Grade: 86.6

The former Buffalo Bills cornerback allowed an average of just 0.82 yards per coverage snap last year, which ranked 14th among the 124 cornerbacks with at least 165 coverage snaps in 2017.

2017 Grade: 77.2

One of the best box safeties in the league, Burnett played 83.1 percent of his run-defense snaps within eight yards of the line of scrimmage last year and racked up 10 run stops as a result. Since 2012, Burnett has now racked up a whopping 93 run stops when lined up in the box, which is tied with Kam Chancellor for the most among safeties in that span

AFC South

CB Aaron Colvin

2017 Grade: 80.0

Throughout the 2017 campaign, Colvin played 83.7 percent of his coverage snaps as the slot cornerback and allowed just 0.76 yards per coverage snap, which was the seventh-best mark among players at the position with at least 110 snaps. Over the last two seasons, Colvin has developed into one of the stingiest slot cornerbacks in the game, and over those last two seasons, he’s allowed just 0.74 yards per coverage snap, which is second to only William Gay among cornerbacks with at least 300 snaps in that span.

DI Denico Autry

2017 Grade: 78.6

Autry quietly had a productive season with the Raiders in 2017, especially in the pass-rush, where he racked up 31 total quarterback pressures – the 10th-most among 3-4 defensive ends. Additionally, an impressive six of those pressures (19.4 percent) were converted to sacks, which was the fifth-highest rate among players at the position with at least 250 pass-rushing snaps.

G Andrew Norwell

2017 Grade: 88.8

Throughout the regular season, Norwell allowed just 13 hurries on his 564 pass-blocking snaps, which resulted in a pass-blocking efficiency of 98.3, the second-best best mark among qualifying guards. He was also the only offensive lineman in the NFL to log at least 500 pass-blocking snaps without allowing either a sack or a quarterback hit, which makes him one of only four guards who have achieved this feat since PFF started collecting data back in 2006.

RB Dion Lewis

2017 Grade: 87.2

One of the shiftiest backs in the NFL, Lewis ended his 2017 season ranked third among backs with an elusive rating of 73.2 and fifth among the same group with a whopping 42 forced missed tackles from his rushing attempts. Since joining the Patriots prior to the 2015 season, on average Lewis has forced a missed tackle every 4.56 rushing attempts, which is the highest rate among the 96 running backs with at least 100 carries in that span.

AFC West

QB Case Keenum

2017 Grade: 85.3

One of the better stories of the 2017 season, Keenum enjoyed a spectacular breakout year. He was at his best when throwing under pressure, where he posted a passer rating of 78.5, the seventh-best mark among quarterbacks. However, when he threw under pressure in the red zone, he completed 11-of-22 passes for 87 yards, five touchdowns and a passer rating of 99.8, which was the best mark among quarterbacks with at least 15 attempts.

WR Sammy Watkins

2017 Grade: 76.2

Throughout the 2017 season, the fifth-year wide receiver generated a passer rating of 122.0 on his 66 targets, which was the fifth-best mark among the 90 receivers with at least 40 targets.

C Mike Pouncey

2017 Grade: 46.5

Throughout the regular season, Pouncey allowed just 12 hurries on his 608 pass-blocking snaps, which resulted in a pass-blocking efficiency of 98.5, the sixth-best best mark among qualifying centers.

CB Rashaan Melvin

2017 Grade: 85.7

Melvin allowed just 29 receptions from 55 targets and just 94 yards after the catch, which was the sixth-lowest mark among the 81 cornerbacks with at least 50 targets. All told, he allowed a passer rating of just 60.3 on throws into his coverage, which was the eighth-lowest mark among the same group.

NFC East

WR Allen Hurns

2017 Grade: 80.7

Running 72.8 percent of his routes from the slot in 2017, Hurns averaged 1.67 yards per route run, the 20th-best mark among receivers last year, which also beat the mark of Cowboys’ incumbent slot receiver Cole Beasley (0.89) by a considerable amount.

WR Cody Latimer

2017 Grade: 76.1

While he saw limited action in 2017, Latimer was certainly efficient when he saw the field and generated a passer rating of 114.3 on his 27 targets, which put him first among Broncos wide receivers with at least 20 targets in 2017.

WR Mike Wallace

2017 Grade: 74.5

The veteran pass-catcher generated a passer rating of 101.8 and posted a catch rate 42.9 percent from his targets of 20 or more yards downfield, which ranked sixth and eighth, respectively, among receivers with at least 20 deep targets in 2017.

Edge Pernell McPhee

2017 Grade: 79.9

McPhee ended the 2016 season with a pass-rushing productivity of 12.4, which was the sixth-best mark among the 57 3-4 outside linebackers with at least 85 pass-rushing snaps.

NFC North

TE Trey Burton

2017 Grade: 75.6

In a season that ultimately ended with a Super Bowl victory, Burton caught 76.7 percent of the passes thrown his way, which was the sixth-best mark among tight ends with at least 30 targets. He was especially effective in the red zone, where he generated a passer rating of 147.3 – the best mark among tight ends with at least five red zone targets.

DI Sylvester Williams

2017 Grade: 76.5

Throughout the 2017 season, Williams produced 12 run stops from his 180 run-defense snaps, which resulted in a run-stop percentage of 6.7 percent – the 47th-best mark among 83 defensive tackles. While the numbers don’t jump off the page, he graded positively on his run-defense snaps, and ended the year with a run-defense grade of 78.2.

2017 Grade: 88.8

The veteran cornerback allowed just 31 receptions from 63 targets last year and added eight pass breakups while doing so. All told, he allowed a passer rating of just 58.4 on throws into his coverage, which was the sixth-lowest mark among the 81 cornerbacks with at least 50 targets. He was especially good at playing the deep ball in 2017 and allowed a miniscule passer rating of just 28.1 when he was tested at least 20 yards downfield.

DI Sheldon Richardson

2017 Grade: 83.8

Richardson was a force in both the run game and in the pass-rush last year and through 17 weeks of the 2017 season, he racked up 36 total quarterback pressures and 22 run stops, which ranked ninth and 17th among defensive tackles this year, respectively. Together, his 61 total impact plays were good for the seventh-most among interior defenders.

NFC South

G Brandon Fusco

2017 Grade: 76.0

Fusco played a grand total of 1,083 snaps throughout the 2017 season, the third-most among guards last year. The veteran guard graded out best in pass-protection, where he allowed 29 pressures from his 654 pass-blocking snaps, for a pass-blocking efficiency of 96.5 – the 32nd-best mark among 61 qualifying guards.

CB Ross Cockrell

2017 Grade: 81.6

The fifth-year cornerback enjoyed his highest-graded season of his career in 2017, thanks to his effectiveness in coverage. All told, he allowed a passer rating of just 69.7 on throws into his primary coverage, which was the 15th-best mark among 81 cornerbacks with at least 50 targets. He was especially stingy when covering the deep ball and allowed just one of the 10 deep passes into his coverage to be caught.

CB Patrick Robinson

2017 Grade: 89.8

Robinson thrived as his team’s primary slot corner in 2017 and all told, he allowed a passer rating of just 65.2 on throws into his primary slot coverage, the fifth-best mark among the 54 defenders with at least 110 slot coverage snaps.

Edge Vinny Curry

2017 Grade: 84.8

A vital cog in the Eagles' Super Bowl-winning defensive line, Curry racked up 47 pressures from his 333 pass-rush snaps in 2017, which resulted in a pass-rushing productivity of 10.8, the 13th-best mark among 67 4-3 defensive ends with at least 135 pass-rushing snaps. A whopping 20 of those pressures came in the fourth quarter of games, the seventh-most among all defensive players in the league.

NFC West

QB Sam Bradford

2017 Grade: 68.9

As the 2018 season approaches, Bradford will be hoping to stay healthy in the hopes that he can recapture the form that he found during his first year with the Vikings in 2016, where he ranked in the top three among quarterbacks in adjusted completion percentage (80.3 percent), deep passer rating (121.5) and passer rating under pressure (87.7). In the 12 years that PFF has recorded data, only two quarterbacks have ended the regular season ranked in the top three in each of those categories, with Robert Griffin III (2012) being the other.

DI Ndamukong Suh

2017 Grade: 91.0

After a move that will strike sheer terror into their NFC West opponents, the Rams will enter the 2018 season with both Suh and Aaron Donald along their defensive line. Suh ended the 2017 season with 43 quarterback pressures, the seventh-most among defensive tackles. He also ended the year with 65 impact plays (total pressures plus defensive stops), which was the 12th-most among all interior defenders.

RB Jerick McKinnon

2017 Grade: 84.6

A true weapon in the passing game, McKinnon ended the 2017 season with a receiving grade of 82.4, which put him seventh among the league’s running backs. He racked up 421 receiving yards at an average of 1.53 yards per route run, which was good for 19th among 55 qualifying players at the position.

DI Tom Johnson

2017 Grade: 77.7

An unsung hero of the Vikings' defensive line, Johnson racked up an impressive 31 total quarterback pressures throughout the season, the 12th-most among the league’s defensive tackles.