The Minnesota Twins signed Santana as an undrafted free agent in December 2007. In November 2012, the Twins added him to the 40-man roster in order to protect him from the Rule 5 draft.[1]
Santana was called up to the major leagues for the first time on May 2, 2014.[2] After a solid start to his career, Santana was placed on the 15-day disabled list on June 27.[3] He spent the season splitting time between center field and shortstop,[4] and he accumulated a .319 batting average, 7 home runs, 20 stolen bases in 101 games, leading all rookies. He finished seventh in American League Rookie of the Year Award voting.[5][6] Additionally, Santana's rookie year batting average of .319 is a Twins franchise record (minimum 130 at bats).[7][8]
Santana began the 2015 season as the Twins' shortstop. He regressed throughout the season, being demoted to the Triple-ARochester Red Wings.[9] He finished the major league season hitting just .215 with no home runs. Santana continued to see his playing time decrease in 2016 due to other players on the team performing better. Despite this, Santana continued to see playing time at shortstop, but an injury cost him half the season. He was designated for assignment on May 5, 2017.[10]
Atlanta Braves
On May 8, 2017, Santana was traded to the Atlanta Braves in exchange for Kevin Chapman.[11] He elected free agency on December 1, 2017, but was resigned to a minor league deal later that month. Santana was assigned to the Triple-A Gwinnett Stripers to begin the 2018 season, and was called up to Atlanta on June 22. He was designated for assignment on July 19, and was outrighted on July 22. He elected free agency after the season.
Texas Rangers
On January 9, 2019, Santana signed a minor league contract, which included an invitation to major league spring training, with the Texas Rangers.[12] He was assigned to the Triple-A Nashville Sounds to open the 2019 season.[13] His contract was purchased on April 13, and he was added to the major league roster.[14] Santana played in 130 games for the Rangers in 2019, slashing .283/.324/.534 with 28 home runs and 81 RBI in 474 at-bats.[15]
Santana only played in 15 contests for the Rangers in 2020, hitting .145/.238/.273 with 1 home run and 7 RBI in 55 at-bats. On December 2, 2020, Santana was non-tendered by the Rangers.[16]
Boston Red Sox
On March 7, 2021, Santana was signed to a minor-league contract by the Boston Red Sox, and received a non-roster invite to spring training.[17] Santana began the minor-league season on a rehabilitation assignment with the High-AGreenville Drive,[18] then played in Triple-A with the Worcester Red Sox.[19] On May 21, Santana was added to Boston's active roster.[20] He made his Red Sox debut that night at Citizens Bank Park against the Philadelphia Phillies, hitting a home run in an 11–3 Red Sox win.[21] He was placed on the injured list on July 9 due to a left quad strain, was sent on a rehabilitation assignment with Worcester a week later, and was activated on July 19.[22] Santana returned to the injured list on July 22 due to a left groin strain.[22] He was activated on September 1,[23] placed on the COVID-related injured list on September 5,[24] and returned to the team on September 7.[25] On September 11, he was again placed on the COVID-related injured list.[26] Overall with Boston during the regular season, Santana played in 38 games while batting .181 with five home runs and 14 RBIs.[27] He appeared in five postseason games, batting 0-for-3, as the Red Sox advanced to the American League Championship Series.[27] He also appeared in 20 minor league games, batting .343 with six home runs and 12 RBIs.[28] On November 3, Santana elected to become a free agent.[29]
On April 4, 2022, Santana was suspended by MLB for 80 games after violation of their Joint Drug Prevention and Treatment Program, testing positive for Boldenone.[30]
On July 28, 2022, Santana was re-signed by the Red Sox to a minor-league contract.[31] On August 20, 2022, he was released and became a free agent.[32]