[2][3][4] On November 20, 2014, Díaz was added to the Pirates' 40-man roster to protect him from the Rule 5 draft.

[9][10][6] He was the Pirates' primary backup to Francisco Cervelli in 2017, batting .223/.265/.314 with one home run in 200 plate appearances.

[11][12] He again backed up Cervelli in 2018, improving his offensive production to a .283/.339/.452 slash line with 10 home runs in 277 plate appearances.

Díaz was the Pirates' primary catcher in 2019, but his offense cratered, batting .241/.296/.307 with 2 home runs in 332 plate appearances.

He hit the game-winning home run for the National League in the eighth inning and was named the game's Most Valuable Player.

[17] On August 26, 2024, Díaz signed a minor league contract with the San Diego Padres.

On September 1, the Padres selected Díaz's contract, adding him to their active roster.

He made his postseason debut in Game 2 of the National League Division Series, striking out in his only at bat.

[23][24] He was slated to play with Colombia at the 2017 World Baseball Classic, but was not permitted by the Pirates organization due to injury reasons.

[citation needed] He was named to the Colombian roster for the 2023 World Baseball Classic, where he shared catching duties with Meibrys Viloria.