CHARLOTTE, N.C. -- Carolina Panthers wide receiver Steve Smith downgraded himself Thursday, saying his return from a sprained left knee didn't go as well as he had hoped in his second practice back from the injury.

"Seventy-one [percent] yesterday," Smith said. "I think I overdid it. Fifty-seven [percent] today. Just went down."

Asked if he considered it a setback, the team's all-time leading receiver said, "If we're on a curve, no. If we're on a curving grading system, there is no setback. If there's no curve, then it's a setback."

Smith sprained the knee in a Dec. 22 game against New Orleans. He did not play in the regular-season finale at Atlanta.