David Ortiz responds to questions during his news conference on Saturday, in which he responded to major revelations about performance use. (Frank Franklin II/Associated Press)

Boston's David Ortiz denied taking steroids during a news conference at Yankee Stadium on Saturday, saying that legal supplements in his system might have landed him on a 2003 list naming baseball players who took performance enhancers.

Big Papi was responding to a New York Times report that he and fellow slugger Manny Ramirez were on the list, which was seized by the U.S. government.

Ortiz discussed the matter before the Red Sox's game against New York.

"I definitely was a little bit careless back in those days when I was buying supplements and vitamins over the counter — legal supplements, legal vitamins over the counter — but I never buy steroids or use steroids," Ortiz said.

"I never thought that buying supplements and vitamins, it was going to hurt anybody's feelings," he said. "I want to apologize to fans for the distraction, my teammates, our manager.

"This past week has been a nightmare."

Ramirez, who was part of the World Series-winning Red Sox team with Ortiz in 2004, just finished serving a 50-game suspension for using banned performance-enhancers.

Sammy Sosa is reportedly on the 104-man list as well, and in February Sports Illustrated named Alex Rodriguez to it. Rodriguez subsequently admitted to having taken performance-enhancers.

Can't confirm results

Ortiz said when he met with union lawyer Michael Weiner in 2004, he wasn't told he had tested positive for steroids. Weiner sat beside Ortiz during Saturday's news conference, with Red Sox manager Terry Francona standing behind and to the side.

Weiner, who has been designated to succeed union head Donald Fehr, said because the list is under court seal, the union can't confirm to Ortiz he tested positive, only that he was on the list.

He added that some then legal nutritional supplements could have sparked a positive, and that some scientific questions remain over the 2003 tests.

A player alleged to be on the list "finds himself in an extremely unfair position," Weiner said. "His reputation has been threatened by a violation of the court's orders, but respect for those orders now leaves him without access to the information that might permit him to restore his good name."

Big Papi said he has tested negative 15 times since baseball's crackdown on performance-enhancers began in 2004. The Red Sox issued a statement backing him as well.

"There are substantial uncertainties and ambiguity surrounding the list of 104 names," the Red Sox said. "David Ortiz is a team leader, and his contributions on the field and in the community have earned him respect and a special place in the hearts of Red Sox Nation."

MLB weighs in

Earlier in the day, Major League Baseball released a statement saying that at least eight players on the list tested clean for performance enhancers, asking fans to withhold judgment on players whose names were released .

"Given the uncertainties inherent in the list, we urge the press and the public to use caution in reaching conclusions based on leaks of names, particularly from sources whose identities are not revealed," Major League Baseball said in a statement.

The 2003 survey was designed to determine whether baseball needed mandatory random drug testing with penalties starting in 2004 — a five per cent threshold for positives would trigger future testing.

Baseball said in November 2003 that five to seven per cent of the of 1,438 anonymous tests in that year's survey were positive for banned substances, which works out to 72 to 101 tests.

Though the exact number was in dispute, the sides agreed it was clearly above the threshold and didn't determine the exact number.

With files from The Associated Press