The team made the move before Tuesday's game against the Boston Red Sox.
The Orioles said candidates to take Cashner's Wednesday spot in the rotation include middle relievers Yefry Ramirez and Miguel Castro.
Cashner (2-8) was the losing pitcher Friday as the Orioles lost 5-1. He allowed three runs and nine hits in six innings in losing his third straight start.
The 31-year-old right-hander has received three runs or fewer in support in 12 of his 13 starts.