Polanco signed with the Minnesota Twins as an international free agent in 2009, receiving a $725,000 bonus.

He again briefly returned to the Twins in late July, batting 2-for-7 with 1 RBI in three games, before finishing out the season in Triple-A.

[11] After the season, both MLB.com and Baseball America ranked Polanco near the bottom of their top 100 prospects lists.

He was demoted back to Triple-A for two months starting in late May, but returned to the Twins on July 30.

[14] In 2017, Polanco was the primary shortstop for the Twins, hitting .256 with 13 home runs, 74 RBIs, and a career high 13 stolen bases in 133 games.

[15] He made his postseason debut, batting 1-for-4 and scoring twice as the Twins lost to the New York Yankees in the Wild Card Game.

[16] On March 18, 2018, Polanco was suspended for 80 games after testing positive for stanozolol, a performance-enhancing drug.

[14] During spring training in 2019, Polanco signed a five-year contract extension worth $25.75 million and club options for the 2024 and 2025 seasons.

[20] Polanco was the American League starting shortstop in the All-Star Game, besting Gleyber Torres and Carlos Correa in fan voting.

[35] On September 30, Baldelli named Polanco and Kyle Farmer the unofficial co-managers of the game, assisting him in exchanging lineup cards and making pitching substitutions.

[14] While the Twins won their first postseason series in 21 years,[37] Polanco hit poorly, going 4-for-21 in the playoffs with a home run in Game 1 of the ALDS.

[39] On January 29, 2024, the Twins traded Polanco to the Seattle Mariners for pitchers Anthony DeSclafani and Justin Topa, prospects Gabriel González and Darren Bowen, and cash.

[40] In 118 games for Seattle, Polanco slashed .213/.296/.355, the worst batting average and on-base percentage of his career, with 16 home runs and 45 RBI.

[42] On October 10, Polanco underwent surgery to repair the patellar tendon in his left knee.

[43] On November 1, the Mariners declined his $12 million option for the 2025 season, making him a free agent.

[47] Polanco grew up playing baseball with future Twins teammate Miguel Sanó.