Considered one of the best defensive first basemen in the majors, Walker is a three-time Gold Glove Award winner.

He was later claimed off waivers in 2017 by the Diamondbacks and became their regular first baseman after Paul Goldschmidt was traded following the 2018 season.

He also helped the team reach the 2012 College World Series, where they lost to the Arizona Wildcats.

[4] The Baltimore Orioles selected Walker in the fourth round of the 2012 Major League Baseball draft.

[13] On September 20, he had his first multi-hit game, including his first career major league home run, off Boston Red Sox starter, Rubby De La Rosa.

The Atlanta Braves also put a waiver claim on Walker, but lost due to the order.

[16] On March 28, 2017, Walker was waived by the Reds and claimed by the Arizona Diamondbacks who assigned him to the Reno Aces of the Pacific Coast League (PCL).

The following year, he hit a career-high 36 home runs and drove in 94 RBI while winning his first career Gold Glove Award.

[20] On January 13, 2023, Walker agreed to a one-year, $6.5 million contract with the Diamondbacks, avoiding salary arbitration.

He also helped lead the Diamondbacks to the 2023 World Series, where they lost to the Texas Rangers in five games.