"We were made aware that newly signed UFC competitor Joe Riggs was involved in an unfortunate accident last night," the UFC said in a statement Tuesday. "While cleaning his permitted firearm (a pistol), the gun discharged, injuring his hand and upper thigh. Riggs was transported to a nearby hospital in Arizona where he is being treated by physicians. We wish Joe a speedy recovery."
The 31-year-old Riggs, who last fought in the UFC in 2006, was slated to face welterweight Paulo Thiago on Sept. 13 on a televised card in Brasilia, Brazil.
The UFC said a replacement opponent for Thiago will be announced shortly.
Riggs (28-9-0) made his UFC debut at UFC 49 in August 2004, submitting Canadian Joe Doerksen. His UFC fight card includes a hospital brawl with Nick Diaz after the two fought at UFC 57.