Newton went down in Thursday's preseason game against the New England Patriots and was seen wearing a walking boot. He returned to practice in a limited fashion Monday.
"He's basically just striding [his throws] out right now, not driving off of his leg or anything like that," Rivera told reporters Monday of Newton's participation. "I didn't get the number of how many throws he made, but he threw it and threw it pretty well today, so we're excited. He didn't really drop back."
Newton is already coming off shoulder surgery, which has him doing exercises in the pre-practice session to keep his throwing arm loose. The shoulder injury limited him throughout last season on shorter and more intermediate throws, and he played in only 14 games.
Newton's shoulder is not considered an issue heading into the regular season, but the foot could wind up being a lingering problem. If Newton is at all hampered, he could struggle with his mobility, thus limiting a large portion of his game. Newton holds the NFL career rushing touchdowns record for a quarterback, and he's one of four signal-callers in league history with 4,000 rushing yards.
The Panthers were able to protect Newton by getting the ball out of his hands quickly last season and may need to follow a similar pattern in 2019 to preserve his health.
That said, the fact that Rivera has little doubt he'll be on the field is a promising sign. Kyle Allen and Will Grier are the two quarterbacks immediately behind Newton on the depth chart.