The Baltimore Orioles initially had said that they would not promote their top pitching prospect, right-hander Dylan Bundy.
A pennant race and an 18-inning game have a way of changing a team's best-laid plans.
Bundy, 19, is heading to the majors.
The Orioles informed Bundy early Wednesday morning that they were promoting him from their Instructional League team in Florida.
Bundy is expected to join the team in time for its series finale against the Seattle Mariners on Wednesday night at 10:10 p.m. ET.
The Orioles need a fresh arm - they used seven relievers for a combined 12 2/3 scoreless innings in their 4-2 victory over the Mariners on Tuesday night.