The MMA veteran was suspended one year by the Kansas Athletic Commission after he tested positive for a banned substance in relation to an in-competition drug test at Bellator 159, the commission announced Friday. Guillard was also fined $10,000.
The substance was not a performance-enhancing drug, the commission wrote in a release. But the Kansas Athletic Commission is not legally able to release the name of the specific substance.
Guillard, 33, fought and beat David Rickels at Bellator 159 on July 22 in Mulvane, Kansas. That result will be overturned into a no contest.
The Kansas Athletic Commission said it learned of the failed drug test Aug.