The report says Riddle was found to have marijuana in his system, while Rivera was caught with an undisclosed over-the-counter stimulant.
Riddle (7-3) has fought all 10 of his professional bouts inside the Octagon. He earned Submission of the Night honors when he defeated Chris Clements at the card.
Rivera (9-2) improved to 2-0 when he topped Roland Delorme. Both Riddle and Rivera declined to appeal their punishments.
The Calgary Combative Sports Commission suspended both fighters for 90 days, dating back to the July 21 card. Neither fight result was changed.
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