Triple-A St. Paul placed Rojas on its 7-day injured list Aug. 22 due to a right oblique strain, Aaron Gleeman of AaronGleeman.com reports.
While the 23-year-old lefty profiled as a potential candidate to join the Twins when the active roster expands to 28 men Tuesday, the oblique injury may take a potential promotion off the table for a bit. Before being optioned back to Triple-A earlier in August, Rojas compiled a 3.34 ERA, 1.52 WHIP and 34:22 K:BB in 29.2 innings over 12 appearances (four starts) for Minnesota.