The team announced Tuesday it signed Kyle Allen, who was set to become an exclusive rights free agent, to a one-year contract.
NFL Network Insider Ian Rapoport reports the deal is for $585,000.
Allen started 12 games in 2019 after Newton went out with a foot injury that iced the former NFL MVP's season after two games.
The 24-year-old Allen completed 62 percent of 489 attempts for 3,322 yards at 6.8 yards per attempt, added 17 touchdowns and 16 interceptions for an 80.0 passer rating, and took 46 sacks in 13 appearances.
After the Panthers won four straight games last season in Allen's first four starts, the wheels came off for the club and quarterback. Allen struggled down the stretch behind a rickety offensive line as defenses took away his initial reads, and he airmailed numerous deep shots.
First, Newton needs to get healthy after missing 16 games the past two seasons and dealing with multiple injuries to his shoulder and foot.
With the starting gig yet to be sorted out, pending Newton's rehab, the backup situation in Carolina with Allen and Grier appears to be set.