The benching came two days after Richardson asked to come out of Sunday's game against the Houston Texans for one play because, as he told reporters, he "was tired."
Colts coach Shane Steichen said Monday that he was evaluating the quarterback situation, adding that Richardson's request to come out of the game would not be a factor in his decision.
Richardson was 10-of-32 for 175 yards in Sunday's 23-20 loss at Houston.