Sean Sherk, aka ‘The Muscle Shark,’ announces his retirement

Kevin Iole

Sean Sherk, one of the top fighters in the early days of the Zuffa-owned UFC, announced his retirement on Monday. A former lightweight champion, the 40-year-old Sherk hadn't fought since defeating Evan Dunham on Sept. 25, 2010, at UFC 119.

He tried to return several times, but was plagued by a series of injuries and was finally forced to retire.

Sherk retires with a 38-4-1 overall mixed martial arts record and a 9-4 record in the UFC. He defeated Kenny Florian at UFC 64 on Oct. 14, 2006, to win the vacant lightweight title. He successfully defended it against Hermes Franca at UFC 73 on July 7, 2007, but tested positive for the anabolic steroid nandrolone following the bout.

He was initially suspended for a year by the California State Athletic Commission, but he denied the allegations and on appeal, the suspension was reduced to six months.

Sherk also had notable wins over Nick Diaz and Tyson Griffin. His losses were all to men that held a UFC title at some point in their careers -- Matt Hughes, Georges St-Pierre, B.J. Penn and Frankie Edgar.

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