NEW YORK (Reuters) - Memphis Grizzlies guard O.J. Mayo was suspended for 10 games after testing positive for a banned steroid, the NBA said on Thursday.

Mayo, taken with the third overall pick in the 2008 draft by the Minnesota Timberwolves, said in a statement that the positive test was the result of taking an over-the-counter supplement that contained the banned steroid DHEA (dehydroepiandrosterone).

"I'm extremely disappointed that I'm going to miss the next 10 games, particularly as our club is making a push for the playoffs," Mayo said in a statement.

"I had no idea that the over-the-counter supplement that I took was a substance banned by the NBA.

"It was an honest mistake, but I take full responsibility for my actions.

Mayo, the runner-up to the Chicago Bulls' Derrick Rose for the Rookie of the Year honors in 2009, has appeared in 45 games this season averaging 12.2 points.

(Writing by Steve Keating in Toronto; Editing by Greg Stutchbury)