Smith suffered the injury while trying to catch a pass in the end zone from Cam Newton. Smith came up with the catch but was called for offensive pass interference, nullifying the score. He left the game holding his left hand and trainers almost immediately took him to the locker room and missed an entire series before returning just before halftime.
Smith had two receptions for 27 yards receiving at the time.
Earlier, Carolina's Charles Johnson left the game after taking a knee to the head from fellow defensive end Greg Hardy. Johnson was taken to the locker room after trainers tested him for a concussion on the sideline.
Johnson has not returned.
Johnson, tied for sixth in the league with 8 1-2 sacks, injured his head when he collided with Hardy's knee as they were applying pressure on quarterback Josh Freeman in the backfield late in the first quarter. Both Johnson and Hardy remained on the ground for several minutes while being attended to by trainers.
Hardy got up limping, but did return on the next series to get a sack.