Panthers coach John Fox said Smith and Lucas returned to Charlotte, about 80 miles away, after the fight. Neither player was present for the team's second practice Friday night.
The Panthers didn't provide an update on the extent of Lucas' injuries and club officials declined to say if the volatile Smith, the team's top receiver, would be suspended.
"We're going to handle this matter internally," general manager Marty Hurney said.
While training camps often include shoving matches between teammates, this melee occurred on the sidelines and after both players had taken off their helmets in a break for starters during a special teams drill. It was unclear what provoked the fight. While the two have routinely jawed at each other in practice since Lucas signed with Carolina in 2005, they've never come to blows in view of reporters.
"When that happens on the field, usually guys have helmets on," quarterback Jake Delhomme said. "But this happened on the sidelines, so it probably wasn't a good idea."
When attention turned from the field to the fight, several players and Fox rushed to the scene. Fox tried to separate the two, but it took linebacker Jon Beason to pull Smith off Lucas.
Lucas walked to a tent, holding a hand to his face while accompanied by a trainer. Smith was then escorted there by receiver Muhsin Muhammad to talk to Lucas.
"Steve was probably a little remorseful for what happened," Muhammad said. "He was trying to apologize, so I was walking with him just to be there."
After being treated for several minutes, Lucas walked to a nearby cart and was taken to the locker room.
Smith spent several minutes talking to kicker John Kasay on an adjacent field before he was escorted to the locker room by Hurney as practice continued.
"Anytime something like that happens you're obviously disappointed," Fox said. "It's part of football and you deal with it."
The coach had an extended talk with the team after the workout. Delhomme said Fox warned the players not to retaliate against Smith.
"I don't anticipate this having any lingering effect on this team," Delhomme said. "We were talked to and things were squashed. That's it. That's the way it is. It happened. There will be no retaliation by anybody on anything. When you look at the schedule we don't play the Panthers this year. So we need to be smart when we're out there."
