"I can't stress enough that I'm not 100 percent yet," Newton said.
At one point Carolina's trainer Ryan Vermillion came over to check on the fourth-year quarterback during practice, but Newton said it was just precautionary.
"It's just going to take treatment and time," Newton said, adding that his rehab is right on schedule.
Coach Ron Rivera said the Panthers will take it slow with Newton, making sure to avoid any potential setbacks.
He said Newton will continue to undergo treatment on a daily basis, but was thrilled to see the team's leader back on the field.
Rivera said he hopes to have Newton available for all four preseason games.
"It was good to see Cam out there," Rivera said. "He's a little rusty in terms of his quarterback to running back exchange. But he's working himself back in and he has to work those techniques. But it was nice to see him make some nice throws."
Rivera said Newton's footwork still needs to improve.
"A big thing is developing that footwork and getting that flexibility back in that ankle," Rivera said. "As he practices and goes through day by day we have to be smart with it. I think he will work back into shape pretty soon."