The 30-year-old passed a physical Monday that was organized by the team and his agency, a source told ESPN's Adam Schefter.
Newton referred to himself as "unemployed" in an Instagram video Monday after his presumed replacement, Teddy Bridgewater, put pen to paper on a three-year contract worth over $60 million.
The Panthers tried to trade Newton and held conversations with the Chicago Bears and Los Angeles Chargers, but Carolina couldn't find a taker for his contract, according to Ian Rapoport of NFL Network. Newton, who's struggled with injuries the last two seasons, is due $19.1 million in 2020, the final year of his deal.
Newton was drafted first overall by Carolina in 2011. Aided by his unique charisma, he quickly ascended to stardom. He captured MVP honors in 2015 while leading the Panthers to an appearance in Super Bowl 50, where they fell to the Denver Broncos.
Newton's future in Carolina was in doubt from the moment the team hired Matt Rhule, who was known for rebuilding college programs, as its new head coach. The signal-caller seemed confident that he would stick with the Panthers, though, saying at the end of January that he came out of a meeting with Rhule, general manager Marty Hurney, and owner David Tepper feeling "inspired."