B.J. Raji -- Raji once was a dominant force in the middle of Green Bay's defense. The Packers made him the ninth-overall pick in the 2009 NFL Draft, and he became a full-time starter during his second season. Raji started all 16 regular-season games and anchored a Super Bowl-winning defense from his nose tackle position in 2010.
Although Raji made the Pro Bowl in 2011, his statistics have steadily sunk since recording 6.5 sacks and 39 stops during the Packers' Super Bowl season. He'll be put to the test this year, as he attempts to come back from a biceps injury that cost him the entire 2014 season.
Casey Hayward -- Hayward has been a productive slot cornerback. Through three NFL seasons, he has recorded nine interceptions. Last year, he had an 82-yard pick-six and a 49-yard fumble return for a touchdown, so he also has a knack for making explosive plays.
This season, however, presents a new challenge for Hayward. He is the favorite to start on the outside, opposite Sam Shields. His competition is stiff, though, with Damarious Randall and Quinten Rollins -- Green Bay's first- and second-round picks in this year's draft, respectively -- breathing down his neck. Also in a contract year, Hayward must boost his market value by proving he is starting caliber.
Nick Perry -- When the Packers selected Nick Perry in the first round of the 2012 NFL Draft (28th overall), they expected him to make a major difference on defense. That hasn't been the case so far. Through three seasons, he has struggled with injuries and failed to hold onto a starting job.
Perry has never reached 30 tackles in a single season, and he only has 9.0 career sacks. The Packers did not pick up the fifth-year option on his rookie deal, meaning the pressure is on Perry to prove himself in 2015. That's a tall order for someone who underwent offseason shoulder surgery.
Jared Abbrederis -- Abbrederis is only going to second NFL season, but he's already facing a make-or-break year in a cutthroat wide receiver competition. The fifth-round selection in last year's draft spent his entire rookie season on injured reserve with a torn ACL in his right knee.
Although Abbrederis has since recovered from that injury, a concussion sustained on the first day of training camp has led some to question his durability. With hungry young receivers in Jeff Janis and third-round rookie Ty Montgomery eager to eat up his reps, Abbrederis must do something soon in order to save his NFL career.
Don Barclay -- Since making the team as an undrafted rookie in 2012, Barclay has developed into a valuable peg in Green Bay's offensive line. He started all but two games at right guard during his second NFL season, then tore his ACL and missed all of last year.
The Packers moved on without Barclay's services in the starting lineup, but they did retain him on a one-year tender as the team's top backup. Now heading toward unrestricted free agency for the first time, Barclay must step up if called upon. He can set a quality market value by playing well when one of Green Bay's starters needs a reliever.