The 27-year-old has been optioned to Triple-A Toledo.
Left-hander Zach Logue has been designated for assignment by the Tigers to create room for Díaz on the 40-man roster. The Tigers will promote a position player from Triple-A Toledo when shortstop Javier Báez gets placed on the bereavement list before Tuesday’s game.
Díaz, a second-round draft pick by the Arizona Diamondbacks in 2014, has hit .179 with nine home runs, 55 walks (9.5% walk rate), 146 strikeouts (33.3% strikeout rate) and a .269 on-base percentage over 151 games in parts of four MLB seasons with the Miami Marlins (2019-21) and Giants (2023).
He hit .053 (1-for-19) with two walks and seven strikeouts in six games with the Giants in three short stints this season. In his MLB career, Díaz owns a .188 batting average in 387 plate appearances against right-handed pitchers and has experience at second base and third base on defense.
The Giants acquired Díaz from the Marlins in exchange for cash considerations in April 2022. That trade happened when Tigers president of baseball operations Scott Harris served as the general manager of the Giants.
Díaz played 26 games for Triple-A Sacramento this season, hitting .240 with seven home runs, 12 walks (11.1% walk rate) and 38 strikeouts (35.2% strikeout rate). He also posted a .324 on-base percentage.
Logue, whom Díaz replaced on the 40-man roster, logged a 7.36 ERA with two walks and 10 strikeouts across 11 innings in three relief appearances with the Tigers this season. The 27-year-old had a 6.22 ERA with 33 walks and 61 strikeouts over 63⅔ innings in 19 games (15 starts) with Triple-A Toledo.