The Twins announced Ober was removed from his start in Thursday's game against the Tigers due to right groin tightness, Chris McCosky of The Detroit News reports.
Ober was in line for the win at the time of his departure, as he exited with a 2-1 lead after giving up an earned run on six hits and two walks while striking out three over 3.2 innings. The Twins are labeling Ober as day-to-day, but he'll presumably need to complete a bullpen session without incident in the next two or three days to make his next turn through the rotation. He tentatively lines up to return to the mound Tuesday in Baltimore.