Packers rookie CB Casey Hayward has lived up to his reputation as an instinctive, ball-hawking playmaker. He leads Green Bay with four interceptions (US Presswire)

The Packers had eight picks in the 2012 draft and spent the first six of them on defensive players. Four of those rookies have had major roles and helped to improve what had been the worst defense in the NFL in 2011.

As Green Bay (6-3) prepares for a stretch run that includes five divisional matchups in its last seven games, we evaluate each rookie and rate his impact on the team, on a scale of 1-10.

Round 1, pick 28 (28th overall) -- OLB Nick Perry: A defensive end at USC, Perry struggled early on to transition to left outside linebacker opposite Clay Matthews in Green Bay. A physical specimen, Perry played the run better than expected and showed his raw athleticism on a few pass rushes (two sacks), but lacked non-bull rushing moves to beat linemen. He suffered a wrist injury in the season opener that he tried to play through, but it ultimately ended his season last week. Impact rating: 4

Round 2, pick 19 (51st overall) -- DE Jerel Worthy: Like Perry, Worthy was drafted high out of Michigan State to provide juice to the Packers’ previously impotent pass rush. There have been concerns about both his motor (in college he had a reputation for taking plays off) and his discipline (he jumped offside far too often in camp and preseason). Still, he’s shown a talent for getting into the backfield, with two sacks and two tackles for loss. He missed Green Bay’s Week 9 game before the bye with a concussion, but returned to practice this week and should continue to get better with more snaps. Impact rating: 5

Round 2, pick 30 (62nd overall) -- CB Casey Hayward: What the Packers knew when they took Hayward out of Vanderbilt was that he was an instinctive, ball-hawking playmaker who had 15 interceptions in college. He’s been the same player in the NFL, making several dazzling plays and leading the Packers in interceptions with four. He’s tackled well and covered better than expected for a first-year player. After injuries to slot corner Charles Woodson and outside CB Sam Shields, Hayward stepped in and seamlessly filled the roles. He was the October NFC Rookie of the Month. Impact rating: 8

Round 4, pick 37 (132nd overall) -- DL Mike Daniels: Daniels came to Green Bay out of Iowa as a stout, undersized (6-foot, 291 pounds) hard worker who could be an interior pass rusher in nickel packages. With far fewer snaps than Perry or Worthy, Daniels has the same number of sacks (two). He’s shown an ability to be disruptive and get penetration inside. He doesn’t have the size to be an every-down or early-down lineman, but he’s done well with limited opportunities. Impact rating: 5

Round 4, pick 38 (133rd overall) -- S Jerron McMillian: A small-school product out of tiny Maine, McMillian has had to prove his physical, hard-hitting reputation could stand up in the NFL. For the most part, he has. He’s been as good as advertised as a run defender, a sound tackler in the secondary and better than expected in coverage. He was given the majority of the opportunities at nickel safety early in the season, but mental mistakes cost him. Now he splits time with second-year S M.D. Jennings, but there’s plenty of potential in McMillian. Impact rating: 6

Round 5, pick 28 (163rd overall) -- ILB Terrell Manning: Manning probably could’ve used another year of seasoning at North Carolina State. He came out a year early based on some flashes of big-time playmaking ability, though -- dealing with an undisclosed-at-the-time illness -- he was practically invisible in training camp, a nonfactor in preseason and thought to be on the roster bubble. He’s played well on special teams but hasn’t had a chance to do anything more than that. With the Packers thin at both inside and outside linebacker, it’s conceivable Manning could work himself into some defensive snaps if he makes major strides and stays healthy. Impact rating: 3

Round 7, pick 34 (241st overall) -- OT Andrew Datko: The knock on Datko, who had ideal size (6-6, 315) and good feet coming out of Florida State, was his oft-injured shoulder. Datko clearly was overmatched in training camp and preseason and desperately needed to add power, especially strength in his shoulder. He was put on the practice squad, where it’s difficult to gauge his progress, but with RT Bryan Bulaga placed on injured reserve this week, Datko has a slight chance to be called up to active duty. Impact rating: 1

Round 7, pick 36 (243rd overall) -- QB B.J. Coleman: Big arm, great size (6-3, 233), good personality; too inaccurate, too small a school, underwhelming results against low-level competition. That was the draft overview of Coleman coming out of Tennessee-Chattanooga. Standing on the field in his Packers uniform in training camp, he certainly looked the part of a pro quarterback. He occasionally showed off his arm strength on deep throws, but more often in camp and preseason, he looked flustered and misfired on his throws. He’s been on the practice squad all season, where he’ll no doubt remain for the duration of 2012. Impact rating: 1

Undrafted free agent -- OLB Dezman Moses: An athletic, unheralded and indefatigable player out of Tulane, Moses turned heads in minicamp and training camp with his unrelenting effort and raw pass-rushing ability. Moses has had some success getting to the quarterback (one sack), especially of late. With increased snaps after Matthews left the Cardinals game with a hamstring injury, Moses had his best performance, finishing with one QB hit and three hurries. Look for continued growth for the improving Moses, who’s smart and eager to learn. Impact rating: 4

Undrafted free agent -- WR Jarrett Boykin: We haven’t seen much from Boykin but we know this: he’s moved ahead of 14-year veteran Donald Driver, the Packers’ all-time leading receiver. Boykin, who was Virginia Tech’s all-time leading receiver, runs excellent routes and has sure hands. He was superb in camp and the preseason and he’s caught all three passes thrown his way (for 16 yards). QB Aaron Rodgers rewards young players who know the playbook, work hard and develop chemistry, like second-year breakout star Randall Cobb. If Boykin follows that recipe, he could see more passes in the final seven games. Impact rating: 3

Undrafted free agent -- S Sean Richardson: Richardson, a teammate of Hayward’s in the Vanderbilt secondary, has the size (6-2, 216) and speed (timed as low as 4.47 in the 40-yard dash) to be a decent safety. He’s physical and a willing tackler, and the Packers can’t have enough of those players. He was a bit of a surprise to make the team out of training camp, but a hamstring injury kept him out for the beginning of the season. He’s only played three games but has performed well on special teams and has the measurables to be a contributor in the future. Impact rating: 3

Undrafted free agent -- OG Greg Van Roten: A smart player with decent size (6-4, 295), the Pennsylvania graduate made the Packers practice squad out of training camp, despite garnering the nickname “Van Rotten” from fans. The Packers like to have young, late-round picks and undrafted players that they can develop. He was added to the active roster a month ago, though Green Bay no doubt hopes he won’t have to play this season. Impact rating: 2

Undrafted free agent -- OT Don Barclay: After Bulaga went on IR this week, Barclay is one play away from being on the field and playing in a meaningful NFL game. He’s the third tackle, behind Marshall Newhouse and T.J. Lang. Barclay (6-4, 305) was a three-year starter and all-conference LT at West Virginia with good feet and quickness. But he just doesn’t have the strength to be anything more than a backup lineman. For now, the Packers are hoping that’s what he remains. Impact rating: 2

Follow Packers reporter James Carlton on Twitter: @CBSPackers and @jimmycarlton88.