Jhon Jairo Romero Rodriguez
- Bats Right, Throws Right
- Height 5' 10", Weight 195 lb.
Jhon Romero pitched for the Colombian national team before reaching the majors.
Romero was signed by Chicago Cubs scouts Manny Esquivia and Hector Ortega in May 2015.  In the summer of '15, he was 0-1 with 8 hits, a walk and three runs (two earned) for the DSL Cubs. With the DSL Cubs 2 in 2016, he had three saves in five games, with a 5.06 ERA. He finally saw somewhat regular action in 2017 and dazzled with the AZL Cubs (0 H, 0 R in 1 IP), Eugene Emeralds (1-0, Sv, 1.80 in 8 G) and South Bend Cubs (0-1, 3 Sv, 0.35 in 13 G). He allowed 15 hits and 11 walks in 41 2/3 IP, striking out 53. He allowed a minuscule .109 batting average. 
Following that breakout year, he joined Colombia's squad for the 2017 Bolivarian Games. In his first outing, he relieved Kevin Escorcia with one out in the bottom of the 8th with a 2-0 lead over defending champion Panama. He retired all five batters he faced, striking out one, for the save. Against Venezuela, he took over for Ángel Vílchez in the 9th with a 2-0 lead and again tossed a hitless, scoreless, shutout inning for the save. Finally, he replaced Kendy Batista in the 9th inning of the Gold Medal Game, with a 6-4 lead over Panama. He again got the save, locking up Colombia's first baseball Gold in the Bolivarian Games since 1973. His three saves led the event - in fact, only one other pitcher (Venezuela's Luis Sanz) had one. 
When Jhon made his major league debut with the Washington Nationals on September 24, 2021, he became the sixth player born on January 17, 1995 to reach the majors, after Randy Dobnak, Michael Hermosillo, Joe Jimenez, Yohander Mendez and Dom Nunez. That tied the record for most major leaguers born on the same day with March 25, 1969, which also begat six players, the most famous of which are Travis Fryman and Dan Wilson.