Injured Carolina Panthers QB Cam Newton rides scooter without helmet

Cam Newton's health remained the issue on Tuesday, one day after the Carolina Panthers quarterback sat out his struggling team's 17-14 loss to the Tampa Bay Buccaneers.

Although he was not in the field, Newton was seen riding a Segway-like scooter without a helmet in downtown Charlotte on Monday. The reigning NFL MVP remains in the league's concussion protocol.

"I'm not going to worry about that," coach Ron Rivera said Tuesday. "The bottom line is he's an adult. We'll go from there."

Dr. Gillian Hotz, the director of the University of Miami concussion protocol at UHealth Sports Medicine, told ESPN that there's plenty of reason to worry with respect to Newton's mode of transportation.

"Pretty high risk, especially without a helmet," she told ESPN. "That would be pretty high risk for potential (to) falling and hitting his head again close to his other concussion."

Newton sustained his first documented concussion in the fourth quarter of a 48-33 loss at Atlanta on Oct. 2, when he took a legal helmet-to-helmet hit from Falcons rookie linebacker Deion Jones on a two-point conversion run.

The 27-year-old Newton did some football-specific work on Monday and could return to practice as soon as Wednesday as the Panthers (1-4) prepare for Sunday's game against the New Orleans Saints (1-3).