The reason behind the cancellation of Saturday's bout between Tim Credeur and Cale Yarbrough was because Credeur tested positive for the prescription drug Adderall.
The two middleweight contestants on "The Ultimate Fighter 7" were scheduled to meet in a preliminary bout on the live season finale event.
According to Thomas Gerbasi of UFC.com, semifinalist Credeur alerted the Nevada State Athletic Commission of the drug during the weigh-ins on Friday, but traces of the drug was still found in his system when test results returned Saturday morning.
Adderall is a drug taken to treat attention-deficit hyperactivity disorder. In addition to what the NSAC considers performance-enhancing effects, it is a banned substance due to potential cardiac dangers brought on from the stress that accompanies fighting.