Newton was dealing with a Lisfranc injury that he suffered in the Panthers' third preseason game. He aggravated the injury in the team's Week 2 loss to the Tampa Bay Buccaneers and didn't see improvement over the last few weeks during rehabilitation.
The franchise quarterback visited with foot specialist Dr. Robert Anderson on Friday in Green Bay, Wisc. The Panthers decided the best course of action was to shut down Newton for the remainder of the season.
"For the past seven weeks, Cam has diligently followed a program of rest and rehab and still is experiencing pain in his foot," Panthers general manager Marty Hurney said in a statement. "He saw two foot specialists last week who agreed that he should continue that path prescribed by the team's medical staff, and that it likely will take significant time for the injury to fully heal.
"We have said all along that it is impossible to put a timetable on this injury. Nobody is more frustrated with that fact than Cam. He's one of the fiercest competitors I've been around during my 20-plus years in the league. At this time, we have decided that the best decision to reach the goal of bringing the foot back to 100 percent is to place Cam on injured reserve."
Before the 2018 season, Newton missed only three starts in seven years. The 2015 NFL MVP missed the last two games of the 2018 campaign due to a shoulder injury that required off-season surgery, then sustained a left midfoot sprain in the third week of the preseason.
The Panthers will move forward with second-year undrafted signal-caller Kyle Allen, who has a 5-1 record as the team's starter this season. Newton had suffered eight straight losses dating back to last season.
Newton, 30, has one year remaining on his current contract. In two games this season, he completed 50-of-89 passes for 572 yards and one interception.