Flande got the nod to make his major league debut on Wednesday. The Rockies also placed right-handed Christian Bergman on the 60-day disabled list with a fractured left wrist.
Flande is the seventh Rockies player to make his major league debut this season, and is the fourth starting pitcher in 19 days to debut with Colorado.
The 28-year-old Flande was 2-9 with a 4.42 ERA in 14 appearances - 13 starts - with the Sky Sox this season.
Bergman broke his wrist on a line drive against Milwaukee on Friday. Initial X-rays showed no damage, but an MRI taken Monday revealed the fracture.
Bergman is 0-2 with a 7.20 ERA in three starts for the Rockies.