Shawne Merriman's lawyer said on Monday that his positive drug test was because of a tainted supplement and will continue to play while appealing his four-game suspension. Attorney David Cornwell said he believed Merriman tested positive for the steroid nandrolone, which is prohibited under the NFL's substance abuse policy. Cornwell said the substance was in a supplement Merriman has been taking. "He did not go into the back alley somewhere and put a needle in his butt for steroids," Cornwell said at a news conference Monday, nearly two hours after Merriman practiced with the Chargers following Sunday's 30-27 loss at Kansas City.