The Panthers have a proven leader setting the tone for the defensive ends. But who will rise up to give Carolina a productive pass rushing duo? It's one of the biggest questions facing this team as it braces for training camp, and there are several young players striving to be the answer.

RETURNERS

Charles Johnson
Vocal leader of the defensive line who is an established pass-rusher and run defender. ... Eight-year veteran has led the Panthers in sacks four of the last five seasons. ... Started every game and finished with a team-high 8.5 sacks and three forced fumbles and ranked first on the team with 44 quarterback pressures in 2014.

Wes Horton
Started 15 games and posted career-highs of 26 tackles, three sacks, eight quarterback pressures and one forced fumble in his second season. ... Solid run-defender who has the ability to take on blocks and set the edge.

Mario Addison
Pass-rush specialist posted a career-high 6.5 sacks and 18 quarterback pressures in 2014. ... Played in every game for the second consecutive season. ... Offers explosiveness off the edge as a situational rusher on third downs.

Kony Ealy
Second-round draft choice played in 15 games and posted four sacks, 12 tackles, nine quarterback pressures and one forced fumble as a rookie. ... Finished strong, recording a sack in each of the last three regular season games. ... Expected to take a big step forward in second year.

Frank Alexander
Played one game in 2014 – the regular season finale – after serving a 14-game suspension for violating the NFL policy and program for substances of abuse. ... Played 28 games with six starts the previous two seasons. ... Former fourth-round pick enters what head coach Ron Rivera calls "make or break" fourth season.

RECENTLY ROSTERED

Rakim Cox
Signed as a free agent after attending rookie minicamp as tryout player. ... Joined the Minnesota Vikings as an undrafted free agent in 2014 but was waived in training camp. ... Recorded 18 sacks as a four-year starter at Villanova.

ROOKIES

Steve Miller
Undrafted free agent played in 35 games with 14 starts at Ohio State. ... Totaled 50 tackles, five sacks, 13.5 tackles for loss and one interception.

Arthur Miley
Undrafted free agent played in 47 games with 36 starts at Southern. ... Totaled 172 tackles, 16 sacks, two forced fumbles, two fumble recoveries and six passes defensed.