Jiménez signed with the Detroit Tigers as an undrafted free agent out of the Puerto Rico Baseball Academy in June 2013.

[1][2] During the 2015 season, Jiménez went 5–1 with a 1.47 ERA, a 0.791 WHIP and 17 saves in 40 appearances for West Michigan, and was named the Tigers Minor League Pitcher of the Year.

[3] During the 2016 season, Jiménez pitched for the Lakeland Flying Tigers, Erie SeaWolves and the Toledo Mud Hens.

[10] Jiménez played for the Puerto Rican national team in the 2017 World Baseball Classic prior to the 2017 season, where he won a silver medal.

[10] He made his Major League debut for the Tigers on April 13 in a game against the Minnesota Twins, pitching a scoreless ninth inning, while recording one strikeout.

He earned his first major league save on June 2, pitching a 1-2-3 ninth inning against the Toronto Blue Jays.

With the 2020 Detroit Tigers, Jiménez appeared in 25 games, compiling a 1–3 record with 7.15 ERA and 22 strikeouts in 22+2⁄3 innings pitched.

[20] Jiménez made 52 relief appearances for the 2021 Tigers, posting a 6–1 record with a 5.96 ERA while striking out 57 batters in 45+1⁄3 innings.

On December 7, 2022, the Tigers traded Jiménez to the Atlanta Braves in exchange for Justyn-Henry Malloy and Jake Higginbotham.