Santana signed with the Los Angeles Dodgers as an international free agent in March 2013. He made his professional debut in 2014 with the Dominican Summer League Dodgers and spent the whole season there, going 2–1 with a 1.05 ERA in twenty games. He pitched 2015 with the Arizona League Dodgers and Ogden Raptors, compiling a combined 2–5 record and 6.42 ERA in 13 games (11 starts), and 2016 with the Great Lakes Loons, posting a 5–9 record and 3.07 ERA with 124 strikeouts in 111.1 innings.[1] He was a Midwest League All-Star with the Loons in 2016.[2]
Santana started 2017 with the Rancho Cucamonga Quakes and was promoted to the Tulsa Drillers during the season.[3] With the two teams, he was 8–7 with a 4.11 ERA in 24 games (21 starts).[4] The Dodgers added him to the 40-man roster on November 20, 2017.[5] He began 2018 with Tulsa but was promoted to the Triple–A Oklahoma City Dodgers in May. In his debut for them, he struck out 11 in six scoreless innings,[6] for which he was named the Pacific Coast League Pitcher of the Week.[7]
Santana was called up to the majors by the Dodgers for the first time on May 30, 2018[8] and made his debut on June 1, picking up the win in relief, despite allowing five runs on six hits in 32⁄3 innings against the Colorado Rockies. He also hit a two-RBI double in his first major league at-bat.[9] He was scheduled to make his first major league start on June 7 against the Pittsburgh Pirates but suffered a right rotator cuff strain while warming up in the bullpen before the game and was placed on the disabled list, where he remained for the rest of the season.[10]
In 2019, he pitched five innings for the Dodgers, across three appearances, allowing four runs on six hits.[11] In 27 appearances for Oklahoma City (17 starts) he was 5–9 with a 6.94 ERA.[4]
After struggling to a 6.00 ERA in 16 appearances to begin the 2021 season, Santana was designated for assignment on June 12, 2021.[12]
Texas Rangers
On June 17, 2021, Santana was traded to the Texas Rangers in exchange for Kelvin Bautista and was assigned to the Triple-A Round Rock Express.[13] He appeared in 63 games for Texas, working to a 3–8 record and 5.22 ERA with 54 strikeouts in 58.2 innings pitched.
New York Mets
On November 15, 2022, Santana was traded to the Atlanta Braves in exchange for cash considerations.[14] On January 13, 2023, Santana signed a one-year, $1 million contract with the Braves, avoiding salary arbitration.[15] On February 26, 2023, Santana was claimed off waivers by the Minnesota Twins.[16]
On March 17, 2023, Santana was claimed off waivers by the New York Mets.[17] He made seven appearances for the Mets, struggling to a 7.04 ERA with five walks and 10 strikeouts in 7+2⁄3 innings pitched. On April 14, Santana was designated for assignment after Jimmy Yacabonis was added to the roster.[18] He cleared waivers and was sent outright to the Triple-A Syracuse Mets on April 18.[19] On May 14, Santana was selected back to the Mets' active roster.[20] After pitching a scoreless inning in a 3–2 loss against the Washington Nationals, Santana was designated for assignment the same day when Brooks Raley was activated from the injured list.[21] On August 16, Santana was selected back to the major league roster.[22] He was designated for assignment for the third time on August 19.[23] Santana elected free agency on August 22.[24]
New York Yankees
On December 6, 2023, Santana signed a minor league contract with the New York Yankees that included an invitation to spring training.[25] He began the season with the Triple-A Scranton/Wilkes-Barre RailRiders, and was promoted to the major leagues on April 5 when Jonathan Loáisiga was placed on the 60-day injured list.[26] In 23 appearances for the Yankees, he struggled to a 6.26 ERA with 19 strikeouts across 27+1⁄3 innings. The Yankees designated Santana for assignment on June 9.[27]