Newton aggravated a sprained left foot in his last outing, a Thursday night loss to Tampa Bay that dropped the Panthers to 0-2. He did not practice all week, working inside with the trainer and going to meetings while wearing a walking boot.
"He's actually coming along well," coach Ron Rivera said Friday on a conference call. "The unfortunate part was last week he was playing on a short week and the foot didn't have time to come back, as far as I understand it. It was pretty sore. It was just one of those things where we have to wait it out and see where it is [next week].
"The one thing we don't want to do is have another setback."
This will be Newton's seventh missed start since he made his NFL debut in 2011 at Arizona. There was no indication on whether Newton would be available for next week's game at Houston.
For Allen, a native of Scottsdale, Arizona, his second career start will be a homecoming. In last year's finale, the then-undrafted rookie out of the University of Houston led Carolina to a 33-14 victory over the New Orleans Saints while Newton was sidelined with a shoulder injury.
This also will be a reunion of sorts for Allen and Cardinals rookie quarterback Kyler Murray. Both were at Texas A&M in 2015 and both transferred to other colleges within a few months of each other, Allen to Houston and Murray to Oklahoma.
Murray went on to become the Heisman Trophy winner and first pick of the 2019 draft. Allen went undrafted after being replaced as Houston's starter in 2017 and forgoing his senior season for the draft.
"It's totally two different paths," Allen said. "It's cool to be back on the field with him. I have a lot of respect for him as a player."
Each quarterback is being counted on to help his team out of an 0-2 hole. While Murray comes in with better credentials and two starts this season, the Panthers are confident Allen can get the job done.
"The best thing I can tell you to do is look at our last game last year," Panthers offensive coordinator Norv Turner said of Allen. "That's the way I would expect him to play. He played at a high level."
Allen completed 16 of 27 pass attempts for 228 yards and two touchdowns with no interceptions to help the Panthers end a seven-game losing streak after a 6-2 start.
Confidence isn't a problem for the 23-year-old. He talked earlier this week about how Roger Staubach, a friend of Allen's father, sent him an autographed picture and how he sent the Hall of Fame quarterback an autographed picture of himself.
When he was 10.
Allen said he's not nervous about the prospects of starting at Arizona's State Farm Stadium, where he never played a down but attended games growing up. "For me, it's weird, but I just look at it as work," Allen said.