Jake Shields' win now a no-contest

The Colorado Boxing Commission has fined UFC middleweight Jake Shields $5,000 and changed his win over Ed Herman in Denver, Colo. on Aug. 11 to a no-contest for testing positive for a "prohibited substance" in a post-fight drug test.

In a statement released by his management team last week, Shields admitted to using an illegal substance prior to UFC 150. He also accepted the six-month suspension, which will expire in February, that was handed down by the commission.

"This was a mistake that I fully regret," Shields stated. "I have shared this issue with my family and the UFC and I have apologized to them, and now I apologize to the fans. I promise this will never occur again in my fighting career."

At this time, the Colorado Department of Regulatory Agency has not confirmed what prohibited substance Shields tested positive for.

Shields (27-6-1) returned to the 185-pound weight class against Herman after a four-fight run in the welterweight division.

A former middleweight champion under Strikeforce, he is 3-2 since signing with the UFC in 2010.