DETROIT — The Houston Astros are calling up right-handed pitching prospect Miguel Ullola from Triple-A to their major-league roster, a person with knowledge of the move confirmed Saturday.
Ullola, 24, projects to join the Astros’ bullpen ahead of Sunday’s series finale against the Tigers and will be seeking his major-league debut. His impending call-up was first reported by The Athletic.
Ullola is already on the Astros’ 40-man roster, added last offseason to protect him from the Rule 5 draft. Baseball America and MLB Pipeline both ranked Ullola as the No. 11 overall prospect in the Astros’ system entering this season.
Signed in 2021 from the Dominican Republic, Ullola rose through the minors as a starter but moved into a relief role last month at Triple-A Sugar Land.
In the minors, Ullola has paired nasty stuff with command issues. He has held opponents to a .190 batting average and struck out 12 hitters per nine innings across parts of six minor-league seasons. He has also walked 6.2 batters per nine over 478 ⅔ minor-league innings.
That profile helped spur his recent shift to the bullpen at Triple-A, exploring if shorter outings could help Ullola operate in the zone more. Ullola posted a 2.70 ERA with six walks and 16 strikeouts in his first 10 relief appearances for Sugar Land.
Just one of those appearances comprised more than an inning. Still, Ullola would provide reinforcement for an Astros bullpen that has been used heavily in the last week while operating short-handed.
The Astros have carried a six-man rotation during a stretch of 13 games with no off day. That ends next Wednesday, perhaps offering the flexibility to bring up an additional reliever.
The Astros did not confirm Ullola’s call-up or announce a corresponding move Saturday. Teng could be a part of a corresponding move, however, given that he has minor-league options and is already seeing an increased workload over recent seasons.
Teng began the season in Houston’s bullpen and moved into the rotation in mid-May. He has thrown 64 innings at the major-league level, posting a 4.36 ERA. Teng totaled 86 ⅔ innings in 2025 between Triple-A and the majors with the San Francisco Giants, and 90 innings between those levels in 2024.
After his start Saturday, in which he allowed five runs, Teng said through an interpreter that “compared to the start of the season, I would say there’s definitely some fatigue and tiredness,” and noted that his inning count is nearing those of the past two seasons. Teng added the fatigue is “still manageable.”
Houston used relievers to cover 27 ⅔ innings across a six-game span through Saturday (including one inning from center fielder Jake Meyers in a blowout loss). It appears Ullola will now help fortify the group.