Rivera, who coached the Carolina Panthers for nine seasons with Newton as his starting quarterback, was asked Monday on 670 The Score in Chicago if he thought Newton has recovered from the injuries that marred his past two seasons. Rivera said he had watched the workout videos that Newton posted on social media.
"He's headed in the right direction," Rivera said on the McNeil & Parkins Show. "I mean, he's probably about as healthy as it gets from what I've seen on video. I think he's ready to bust out.
"I would never bet against the young man, that's for sure."
Newton, who holds most of Carolina's career passing records, missed 14 games last season with a foot injury and the final two games of the 2018 season with a shoulder injury that also required surgery.
He reached an agreement on a one-year, incentive-laden deal with the Patriots on Sunday, league sources told ESPN's Chris Mortensen and Adam Schefter. The Patriots were the only team to make an offer to Newton after he was released by the Panthers in March, according to Schefter.
Rivera, who is now the Washington Redskins' coach, said on 670 The Score that he believes the coronavirus pandemic, which prevented teams from conducting in-person workouts, was the main reason more teams didn't try to sign Newton. As for why Rivera didn't try to bring Newton to Washington, the coach pointed to the presence of quarterback Dwayne Haskins, drafted by the Redskins in the first round last year.
"Honestly, if the circumstances would have allowed us, I would have had no issues with that. I would have been very confident and comfortable in going after him and bringing him to be part of what we're doing here. To me, those circumstances would have been going through an opportunity to see what we have in Dwayne," Rivera said.
Rivera instead brought another former Panthers quarterback to Washington, trading for Kyle Allen earlier this offseason. Rivera said the benefit of being in his first year as the Redskins' coach is that he can be patient with Haskins, who threw for 1,365 yards with seven touchdowns and seven interceptions after being selected with the No. 15 pick in 2019.
"We've been in this tough situation because there was a number of veteran guys that we liked, but we have to find out what we have in the young guy, and that's the benefit of being a new head coach is that we can go ahead and we can be patient," Rivera said. "We can put these guys through workouts and get to know what we have and feel good about it or don't feel good about it, and then we've got to go out and make some changes.
"But until we get that opportunity to know what we have, it would have been very hard to bring in a guy who's had such a solid career, who was league MVP at one time [in 2015], and expect the young guy to get chances to grow. So I just felt that because of our circumstances we could play this slow -- and good for [Newton], he went to New England, which I think is going to be a great spot for him and I think he's going to have a lot of success."
With the Patriots, Newton will be in the mix to help replace Tom Brady, who left to join the Tampa Bay Buccaneers in free agency. The Patriots did not select a quarterback in April's draft, with 2019 fourth-round pick Jarrett Stidham and 11-year veteran Brian Hoyer atop the depth chart.
On Tuesday, wide receiver Julian Edelman welcomed Newton to New England via Twitter:
Rivera was asked what he'd say to those who believe Newton's best days are behind him.
"Don't bet against him," Rivera said. "I really wouldn't. First of all, you got to know who he is and understand what all he's gone through. He's a guy that's always tried to do things, I think, because he's felt the pressure. He felt the pressure of being the No. 1 pick. He felt the pressure of having won the Heisman Trophy and being the No. 1 pick. He felt the pressure of being a Black quarterback, with all this stuff that's been heaped on him.
"He's really had to find his way through it, and he's done a great job with it."