Blanco signed with the Oakland Athletics on April 2, 2018.[3][4] He spent the 2018 season with the High–A Stockton Ports, hitting .291/.342/.406 with one home run, 37 RBI, and 22 stolen bases. He opened the 2019 season with the Double–A Midland RockHounds, hitting .276/.342/.468 with seven home runs, 44 RBI, and 27 stolen bases.[5]
Kansas City Royals
On July 27, 2019, Blanco and Ismael Aquino were traded to the Kansas City Royals in exchange for Jake Diekman.[6] He finished the 2019 season with the Double–A Northwest Arkansas Naturals, hitting .230/.282/.302 with five RBI and six stolen bases.[5] Blanco did not play in a game in 2020 due to the cancellation of the minor league season because of the COVID-19 pandemic.[7] Blanco split the 2021 season between Northwest Arkansas and the Triple–A Omaha Storm Chasers, hitting a combined .277/.350/.441 with 14 home runs, 53 RBI, and 41 stolen bases.[5]
On May 19, 2022, Kansas City selected Blanco's contract to the active roster as a COVID-19 replacement. He made his MLB debut on May 20, recording his first career hit.[8] He appeared in five games for Kansas City, going 2–for–7 in seven plate appearances. On June 3, Blanco was designated for assignment by the Royals.[9] He cleared waivers and was sent outright to Triple–A Omaha on June 7.[10] He spent the remainder of the year in Omaha, hitting .301/.367/.486 with 14 home runs, 61 RBI, and 45 stolen bases across 107 games.
Blanco was assigned to Triple–A Omaha to begin the 2023 season. In 49 games, he batted a stellar .347/.444/.451 with three home runs, 19 RBI, and a career–high 47 stolen bases.[11] On June 12, 2023, Blanco was selected to the major league roster.[12] In 69 games for the Royals in 2023, he slashed .258/.324/.452 with three home runs, 18 RBI, and 24 stolen bases.[13]
On August 17, 2024, Blanco had a career night, hitting two home runs, including his first career grand slam, and driving seven runs in against the Cincinnati Reds.[14]