Grier's release left only two members of Carolina's 2019 draft class, selected by former general manager Marty Hurney, on the roster: first-round pick Brian Burns (defensive end) and sixth-rounder Dennis Daley (offensive lineman).
Grier started the final two games in 2019, going 0-2 and throwing four interceptions to no touchdowns. He showed improvement during the 2021 preseason, scrambling for a 24-yard touchdown in Friday's exhibition finale against Pittsburgh.
But the 26-year-old Charlotte native, who became a star at West Virginia, fought an uphill battle for the backup job under coach Matt Rhule the past two seasons. Walker got the start last season when Teddy Bridgewater was injured and was first up behind Darnold for most of the 2021 preseason.
Walker's ability to make plays with his arm and legs, as he did for Rhule at Temple and the XFL for the Houston Roughnecks, earned him the confidence of the Carolina staff, which Grier never developed.
The biggest question on Walker was his ability to protect the football because of his willingness to take chances downfield. That led to one touchdown pass and five interceptions in the four games he played in 2020.
Walker was 1-0 last season, throwing for 258 yards with one touchdown and two interceptions in a 20-0 victory over Detroit.
Grier remains a possibility for the practice squad, according to a league source. The Panthers also could add a third quarterback for the roster or practice squad.