Luke Kuechly, the Carolina Panthers’ star linebacker, has announced his retirement at the age of 28. He suffered at least three concussions during his eight-season NFL career. “It’s never the right time to step away,” Kuechly said. “But now is the right time for me. It’s a tough decision .... The memories I have from this place and this organization and playing on the field with these guys, they’ll never go away.” Kuechly didn’t specifically mention concussions during his announcement, but did say he no longer felt he could “play fast and play physical and play strong” like he used to. Kuechly was selected to the Pro Bowl seven times and was named all-pro five times. He was the NFL’s defensive rookie of the year in 2012, and helped the Panthers reach the Super Bowl in 2015.