The Nationals promoted Romero from Double-A Harrisburg to Triple-A Rochester on Tuesday, Grant Paulsen of 106-7 The Fan Washington reports.
Romero appeared in three games at the big-league level in 2020, but that was largely a byproduct of the Nationals wanting a power arm out of the bullpen while the team still had visions of contending for the playoffs last season. With minor-league baseball returning to action in 2021, the Nationals shifted their focus back to developing Romero as a starter, but he didn't make his debut in the minors until July 1 while he recovered from a rib injury suffered in spring training. Upon completing a rehab assignment, Romero eventually settled at Harrisburg, where he submitted a 5.31 ERA and 1.48 WHIP in 20.1 innings over six outings. While Romero's surface numbers were ugly, his outstanding peripherals (2.75 FIP, 27.2 K-BB%, 0.89 HR/9) were justification for the Nationals to bump the 25-year-old up to Rochester.