[1][2] As a senior in 2020, he hit .457 with four home runs and 15 RBIs over 16 games before the season was cut short due to the COVID-19 pandemic, and was selected as the Georgia Gatorade Player of the Year.

[20] On March 25, 2023, Cardinals president of baseball operations John Mozeliak announced that Walker had made the Opening Day roster.

[21] On March 30, Walker started in right field for the Cardinals and recorded his first major league hit and run batted in.

[22] On April 5, Walker recorded his first career major league home run off of Michael Tonkin of the Atlanta Braves.

[24] He was optioned to Triple-A Memphis on April 26, and was subsequently recalled to the major leagues on June 2, where he spent the remainder of the season.

[25] Over 117 games (making 115 starts in the outfield and as designated hitter), Walker slashed .276/.342/.445 with 16 home runs and 51 RBIs.