CHARLOTTE – Linebacker Luke Kuechly, the NFL's leading tackler by a significant margin since entering the league, has signed a five-year contract extension with the Panthers through the 2021 season.

Kuechly will play the 2015 season under the fourth and final year of the rookie contract he signed after Carolina selected him ninth overall in the 2012 NFL Draft. In April, the Panthers exercised the fifth-year option Kuechly's rookie contract that now extends through 2016.

"Luke is one of the best young players in the NFL and I'm very excited that the extension is done," general manager Dave Gettleman said. "Like Cam Newton's extension, this contract allows us to do the long-term planning and have the fixed cost that we need to continue to build the best team possible."

Kuechly has 473 career tackles based on press box statistics, 44 more than Tampa Bay linebacker Lavonte David since 2012. Kuechly has paced the NFL in tackles twice in his three-year career. The one year he didn't, in 2013, Kuechly was named NFL Defensive Player of the Year.

The second-leading tackler in NCAA history following a standout career at Boston College, Kuechly assumed a leadership role on defense early in his rookie season when he shifted from the weak side into the middle linebacker role. He was named NFL Defensive Rookie of the Year after pacing the league with 164 tackles.

Kuechly helped forged the Panthers defense his first season into a top-10 unit, a feat the defense has repeated each of the past two seasons. In addition to being named defensive player of the year in 2013, Kuechly was a first-team All-Pro selection and was named to the Pro Bowl following the 2013 and 2014 seasons.

"Luke is a special player and has been a big reason why we've had success on defense," head coach Ron Rivera said. "He has the skillset you want in a middle linebacker – a great first step, the ability to play downhill and drop into coverage – and he has great command of our defense and what we want to do schematically. He's a perfect fit for us and I'm excited we got the deal done."

Kuechly joins quarterback Cam Newton, linebacker Thomas Davis and tight end Greg Olsen as core pieces to sign contract extensions prior to the start of the 2015 campaign.