The 31-year-old defensive end played a pivotal role on many of Carolina's playoff teams, including the 2015 group that lost in Super Bowl 50. Johnson missed nearly half the 2015 regular season with a hamstring injury, but returned to form in the postseason where he logged three sacks and seven tackles over three games.
Johnson was suspended for four of the final five games of the 2017 season for violating the league's PED policy.
Johnson led the team in sacks for four seasons in a five-year stretch from 2010 to 2014. Over that period, Johnson's 52.5 sacks tied for the fifth-highest total in the NFL.