The following is the fifth installment in a series of stories that'll examine the Packers' roster position by position. The series continues with the defensive line.

GREEN BAY—The Packers are getting younger on the defensive line, but it wouldn't be accurate to characterize the shift as a total youth movement.

Ryan Pickett and Johnny Jolly have not been brought back, but the unit still has a couple of experienced veterans, while room is being made for the youth in which the Packers have invested draft picks in recent years to become more seasoned, higher-impact players.

The Packers have two true veterans up front, but it could be more than that, depending on how much the newly acquired Julius Peppers and re-signed Mike Neal line up as down linemen vs. outside linebackers. They'll play both as hybrid players within some of the tweaks Dom Capers made with the X's and O's.

The veterans who are pure linemen are B.J. Raji and Letroy Guion. Raji was removed from the free-agent market with a one-year "prove it" deal that gives him every incentive to re-enter free agency next season in higher demand. He wants to reclaim his old territory of nose tackle.

Also able to play the middle, as well as any other position up front, is Guion. Formerly of the Minnesota Vikings, Guion was plucked from the free-agent market for his versatility. He never played in a 3-4 in Minnesota, but there are no concerns about his ability to adapt.

The rest of the defensive line room is filled with eight players with two or fewer NFL seasons under their belts, including four rookies. Among the four returning players, a key to the Packers' production up front this season could hinge on whether one of the other three joins Mike Daniels in taking his game to a new level.

Daniels is the rising star of the unit, having boosted his sack total from two as a rookie fourth-round pick to 6 ½ last season, plus another sack in the playoffs. He's vocal both on and off the field and has made no secret of his desire for the defense to get meaner and nastier, taking it upon himself to lead the way.

Can the game of either Datone Jones, Josh Boyd or Jerel Worthy rise as Daniels' has? For all the ups and downs of his rookie year, which included a preseason ankle injury that lingered for quite some time, Jones still recorded 3 ½ sacks. If he were to triple his sack numbers as Daniels did from his first year to his second, the 2013 first-round pick would reach double digits.

Boyd was quiet early on last season as a rookie fifth-round pick, a gameday inactive for seven of the first nine games, while he adjusted from Mississippi State's 4-3 to the Packers' 3-4. Jolly's late-season neck injury forced Boyd into action and Boyd showed promise, particularly in the Dallas game, when he recorded a tackle for loss and drew a holding penalty, both against the run.

Worthy, a second-round pick in 2012, enters his third season, but after a second year that was essentially a washout. Rehab from a knee injury suffered in Week 17 of 2012 limited Worthy to a pair of cameo appearances last season, and he sat out all of OTAs and minicamp this spring as well. He has catching up to do and rust to knock off.

Of the four rookies, Khyri Thornton from Southern Miss was the lone draft pick, taken in the third round. "Quick twitch" was the phrase associated with Thornton on draft day, which would lend itself to being an inside rusher in the nickel, though he has the size (6-3, 304) to play end in the base as well.

North Carolina State's Carlos Gray, Miami's Luther Robinson and Colorado State-Pueblo's Mike Pennel are the three undrafted rookies, and if there's a sleeper to watch, it could be Gray. He carries his 313 pounds well and comes in raw, having played just two seasons in college following a redshirt year, with only five starts to his credit. Previously in Countdown to Camp:

• OL - Packers have veteran depth at tackle
  
• WRs/TEs - Nelson, Cobb aim for thousand-yard club
  
• RBs - Thunder and lightning mostly thunder
• QBs - Flynn incumbent at backup QB