LAS VEGAS -- Former UFC light heavyweight champion Lyoto Machida has received an 18-month suspension for failing a doping test.

The U.S. Anti-Doping Agency announced the suspension Wednesday.

USADA says the 38-year-old Machida failed an out-of-competition test in April for a prohibited anabolic agent. The organization says Machida acknowledged using the substance, claiming he didn't know it was banned.

Machida was subsequently pulled from a bout with Dan Henderson.

Machida's ban is retroactive to April, making him eligible to return in October 2017. His suspension was reduced from a standard two-year ban for acknowledging his mistake, USADA says.

Machida held the UFC's 205-pound title from 2009-10. He moved to middleweight and lost a title fight to Chris Weidman in July 2014, starting off a string of three losses in his last four fights.