Carolina Panthers wide receiver Kelvin Benjamin left practice on Wednesday and was listed as a non-participant with a knee injury. Benjamin walked off under his own power, and when asked about the 6-foot-5 receiver, Panthers coach Ron Rivera simply said, "Knee.'' Benjamin has worked on the sideline periodically the past few weeks of practice to strengthen the left knee that he tweaked in a 34-13 loss to New Orleans in Week 3. Benjamin went down awkwardly in the second quarter when tackled from behind after a short catch over the middle.