(This story first appeared on usatoday.com.)

Jon Jones said he “can’t even pronounce” the substance that led to a failed out-of-competition test and his removal from atop Saturday’s UFC 200 card. Both Jones and his manager indicated the positive test at a news conference today, saying it could have been the result of a tainted supplement.

An executive from GAT Nutrition, a sponsor of Jones and other athletes, told USA TODAY Sports that if a supplement was the source of the banned substance, it did not come from his Connecticut-based company.

“Nothing Jon is using from GAT contains anything that is banned,” GAT Nutrition Vice President Mark Post said. “We do extensive third-party testing, and we know he has been tested (with no positives for performance-enhancing drugs) several times. Everything has come up clear. We have no idea what has changed in what he has taken over the last month. We don’t live with Jon and don’t even know what the banned substance is.”

The U.S. Anti-Doping Agency, the independent organization that carries out UFC’s testing program, has not released the specific substance publicly. The substance was flagged after a sample was collected on June 16. Jones faces a ban of up to two years.

“I have taken the same supplements my entire career,” Jones said.

The tainted supplement defense has been used – largely unsuccessfully – by athletes for years. Even if a supplement is found to be have been tainted or adulterated, USADA follows the World Anti-Doping Agency’s code and the principle of strict liability. That means an athlete assumes the responsibility for whatever goes into his or her body.

Post said it had the two supplements that Jones has used for some time – PMP Pre-Workout and an amino acid supplement – sent out to a quality insurance lab before it was distributed to athletes and no banned substances were found.

“We have had no issues with any of our products,” Post said. “That’s what makes me question what (the banned substance) is. We don’t take chances with our athletes.”

The specific substance won’t be revealed until after the case is adjudicated, which includes a test of the “B” sample. Malki Kawa, Jones’ manager, told reporters that Jones would appeal.

Post said his company would withhold a decision on whether to cut ties with Jones until the process is complete.

“We can’t jump to conclusions,” Post said.

For more on UFC 200, check out the UFC Rumors section of the site.

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