In round 15 of the 2020 NRL season, he was included in the Roosters 21-man squad to play the Wests Tigers but was omitted from the side before the game.

[17][18] The following week, he scored his first try in the NRL and set up three others in a pivotal performance as the Roosters went from being 4–18 down to the Cronulla-Sutherland Sharks, to mounting a comeback to win 26–18.

[19] In round 14, Walker kicked the winning field goal as the Sydney Roosters defeated the Gold Coast Titans 35–34.

[20] In round 17, with just under 20 seconds left to play, Walker bizarrely ran 90 metres in the opposite direction before running over the sideline as the Sydney Roosters defeated Canterbury-Bankstown 22–16.

Walker spoke to the media after being demoted saying "I never wanted to get dropped, but I will work as hard as I possibly can to get a spot back in the team".

In July, Walker suffered an ACL sprain whilst playing in the NSW Cup and was ruled out for an indefinite period.

In the first week of the 2023 finals series, Walker kicked a field goal with three minutes remaining to win the match 13-12 against Cronulla.