Contreras signed with the Braves organization in 2015 and made his major league debut on Opening Day in 2020.

He split the 2018 season between the Rome Braves and the Florida Fire Frogs, hitting a combined .285/.347/.436/.783 with 11 home runs and 49 RBIs.

[9] Contreras was activated on July 24, 2020,[10] and made his major league debut that day as a backup catcher.

[13] On May 5, 2021, Contreras hit his first career home run against Washington Nationals pitcher Erick Fedde.

[20] Contreras was named to the 2022 Major League Baseball All-Star Game as an injury replacement for designated hitter Bryce Harper.

His defense at catcher improved significantly, and he won a silver slugger award at the end of the season.