As a true freshman at Washington in 2014, Baker started all 14 games, recording 80 tackles, one interception, and one sack. Following his freshman campaign, Baker was named a Freshman All-American by USA Today. As a sophomore in 2015 he started 12 of 13 games and was named All-Pac-12 after recording 49 tackles and two interceptions. Baker was named a pre-season All-American prior to the 2016 season. Following the 2016 season, Baker earned consensus all-American honors as a result of being named a first-team all-American by The Sporting News and the Football Writers Association of America, and a second-team all-American by the American Football Coaches Association and The Associated Press. On January 3, 2017, Baker announced his decision to forego his senior season and enter the 2017 NFL Draft.
Collegiate statistics
Professional career
Baker attended the NFL Combine and completed all of the combine and positional drills. He participated at Washington's Pro Day and only ran positional drills for over 50 NFL team representatives and scouts. The majority of NFL draft experts and analysts projected Baker to be a second round pick. Although he showed fluidity, athleticism, speed, passion, solid ball skills, and performed well in coverage, many teams were concerned over his lack of size and how that would affect his ability to play in the NFL. He was ranked the top nickelback available in the draft by NFL analyst Mike Mayock, was ranked the second best free safety prospect by NFLDraftScout.com, and the fourth best safety in the draft by Sports Illustrated and ESPN.
The Arizona Cardinals selected Baker in the second round of the 2017 NFL Draft. The Arizona Cardinals traded their second round, fourth round, and seventh round picks in the 2017 NFL Draft to the Chicago Bears in order to move up in the second round and draft Baker with the 36th overall pick. The Cardinals also received a seventh round pick from the Chicago Bears. He was the fourth safety selected in 2017 and one of three Washington defensive backs selected, along with Kevin King and Sidney Jones. On May 25, the Arizona Cardinals signed Baker to a four-year, $6.83 million contract with $3.88 million guaranteed and a signing bonus of $3.10 million. Due to NFL's rules for colleges who follow quarters systems, Baker was unable to attend OTA's or minicamp until he graduated from Washington. He impressed coaches throughout training camp and was named the backup free safety to Tyrann Mathieu to begin the regular season. He made his professional regular season debut in the Arizona Cardinals’ season-opener at the Detroit Lions and made one tackle in their 35-23 loss. On November 19, 2017, Baker earned his first career start after Tyvon Branch suffered a torn ACL the previous week. In his first career start, he collected a season-high 13 combined tackles, deflected two passes, and made his first career sack during a 31-21 loss at the Houston Texans in Week 11. On December 19, 2017, Baker was one of four Cardinals named to the 2018 Pro Bowl as a special teamer. In Week 16, he tied his season-high of 13 combined tackles and broke up a pass in the Cardinals’ 23-0 victory against the New York Giants. He finished his rookie season in 2017 with 74 combined tackles and seven pass deflections in 16 games and seven starts.
2018
On January 1, 2018, Arizona Cardinals’ head coach Bruce Arians announced his retirement. On January 22, 2018, the Arizona Cardinals announced their decision to hire Carolina Panthers’ defensive coordinatorSteve Wilks as their new head coach. Throughout training camp, Baker competed to be the starting strong safety against Tre Boston. Head coach Steve Wilks named Baker the starting strong safety to begin the regular season, alongside free safety Antoine Bethea. He was also named the first-team nickel back with Tre Boston taking over at strong safety in packages that require five defensive backs. In Week 5, Baker collected a season-high 16 combined tackles, deflected a pass, and made a sack during a 28-18 win at the San Francisco 49ers. In Week 6, against the Minnesota Vikings, Baker recorded a 36-yard fumble return for a touchdown in the 27–17 loss. He finished the season second on the team with 102 tackles through 14 games and 13 starts.
2019
In week 2 against the Baltimore Ravens, Baker recorded a team high 11 tackles as the Cardinals lost 23–17. In week 9 against the San Francisco 49ers, Baker recorded a team high 13 tackles and 3 passes defended in the 28–25 loss. In week 10 against the Tampa Bay Buccaneers, Baker recorded a team high 9 tackles and forced a fumble on running back Ronald Jones II which he recovered in the 30–27 loss.
Personal life
Baker's mother started calling him Budda as a baby since his mother thought he looked like a Buddha doll.