NEW YORK — Alex Rodriguez admitted today that he used performance-enhancing drugs from 2001-03 when he played for the Texas Rangers.

"Back then it was a different culture. It was very loose. I was young. I was stupid," the New York Yankees star said in an interview with ESPN. "I was naive, and I wanted to prove to everyone that, you know, I was worth, you know — and being one of the greatest players of all time.

His admission came two days after Sports Illustrated reported he tested positive for steroids in 2003, one of 104 players who tested positive during baseball's survey testing, which wasn't subject to discipline.

"It was such a loosey-goosey era. I'm guilty for a lot of things. I'm guilty for being negligent, naive, not asking all the right questions," Rodriguez said. "To be quite honest, I don't know exactly what substance I was guilty of using."

SI.com reported he tested positive for Primobolan and testosterone.

"And I did take a banned substance and, you know, for that I'm very sorry and deeply regretful. And although it was the culture back then and Major League Baseball overall was very — I just feel that — You know, I'm just sorry. I'm sorry for that time. I'm sorry to fans. I'm sorry for my fans in Texas. It wasn't until then that I ever thought about substance of any kind, and since then I've proved to myself and to everyone that I don't need any of that."

Rodriguez directly contradicted a December 2007 interview with CBS's "60 Minutes," when he said, "No" when asked whether he's ever used steroids, human growth hormone or any other performance-enhancing substance.

"I've never felt overmatched on the baseball field," he said then. "I felt that if I did my, my work as I've done since I was, you know, a rookie back in Seattle, I didn't have a problem competing at any level."