Boston Red Sox Slugger David Ortiz responds to questions during a news conference Saturday in New York.

New York ? David Ortiz said he never knowingly used steroids and that over-the-counter supplements and vitamins likely caused him to land on a list of alleged drug users circulated by the federal government.

Major League Baseball and the players’ union said just because a player’s name was on the list didn’t mean he used steroids.

“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 during a news conference that began about 31?2 hours before his Boston Red Sox played the New York Yankees.

“I never thought that buying supplements and vitamins, it was going to hurt anybody’s feelings.”

MLB said in a statement Saturday that at most 96 urine samples tested positive in the 2003 survey — and the players’ association said 13 of those were in dispute.

The New York Times reported last month that Ortiz and Manny Ramirez were on the list and said in June that Sammy Sosa was on it. In February, Sports Illustrated reported Alex Rodriguez was on the list, and Rodriguez later admitted using Primobolan from 2001-03.

Ortiz said that when he met with union general counsel Michael Weiner in 2004, he wasn’t told he tested positive for steroids. Weiner, who has been designated to succeed union head Donald Fehr, said that because the list is under court seal, the union can’t confirm to Ortiz that he tested positive, only that he was on the list.

“We had this five-minute meeting, and it was a little confusing but I was never told that I test(ed) positive for steroids,” Ortiz said.

Dr. Gary Wadler, who heads the committee that determines the World Anti-Doping Agency’s banned-substances list, said Ortiz’s explanation was believable, given that before January 2005 many over-the-counter substances could cause positive tests.

“It’s entirely conceivable that he was caught up in the same mentality of taking dietary supplements such as protein powders and creatine, believing he was safe as far as drug testing,” Wadler said in a telephone interview with the Associated Press.

Some players past and present — notably Hall of Famer Hank Aaron — have called for the entire list to be released.

“Sure, there are some people who say, ‘Why don’t we just get this story over with and get the list out?”‘ Weiner said. “I think to do that would 1) be illegal, and 2) be wrong. It’s illegal because it’s covered by court order, and it would be wrong because a promise was made by the commissioner’s office and the union to every player who was tested in 2003 that the results would be anonymous.”

Ortiz is against the list becoming public.

“I don’t think that I would really like to see another player going through what I’ve been through this past week,” he said.

The government seized the samples and records in 2004 from baseball’s drug-testing companies as part of the Bay Area Laboratory Co-Operative investigation into Barry Bonds and others. The list of 104 players said to have tested positive, attached to a grand jury subpoena, is part of a five-year legal fight, with the union trying to force the government to return what federal agents took during raids.

Ortiz said he purchased the supplements in both the United States and the Dominican Republic, and that he tested negative about 15 times since baseball’s program with penalties began in 2004 and additional times for the World Baseball Classic.

“I want to apologize to fans for the distraction, my teammates, our manager,” Ortiz said, flanked by Weiner, with Boston manager Terry Francona standing behind and to the side. “This past week has been a nightmare to me.”

The Red Sox issued a statement backing Ortiz.

“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.”

Ortiz said the report that he was on the list weighed on him — since it came out July 30, he is batting .171 with two homers and six RBIs, part of a season-long slump that’s left his average at .219.

“This past week, I’ve been really confused and frustrated,” he said. “I started looking for answers, and nobody gives me an answer.”