For the first time, Woods disclosed that in addition to recovering from reconstructive knee surgery in late 2008, he also tore his Achilles tendon in his right foot late that year.
Woods admitted to undergoing a procedure known as platelet-rich plasma (PRP), which helps speed the healing process. He said he chose Dr. Anthony Galea -- who is under federal investigation in a drugs case -- because of his work with other athletes. Galea came to Woods' house to perform the procedure.
The platelet rich plasma treatment Woods cited was introduced in the 1970s for surgical uses in hospitals. It didn't enter sports medicine until a decade ago. In the 30-minute procedure, a tube of a patient's blood is put in a centrifuge and spun, producing concentrated platelets. The platelets contain growth factors that accelerate tissue repair and regeneration. The platelets then are injected into the injury site.
PRP is gaining popularity among injured "weekend warriors" and their insurers because its $2,000 cost is a fraction of that for potential surgeries.
The procedure is legal under the PGA Tour's drug testing policy.
"I've never taken any illegal drug in my life," Woods said.
Woods said that his agent, Mark Steinberg, has been contacted by federal investigators about Galea, who has been charged with dispensing illegal drugs in both Canada and the United States. Woods vowed his full cooperation.
"They contacted my agent and will get full cooperation whenever they need me, but right now they haven't asked for my time," he said.
Asked why he did not address the issue earlier -- the New York Times first reported Galea's link to Woods in December -- the golfer said it was because he had not had the forum to discuss it, and wasn't asked in the two televised interviews last month.
Woods' world -- and that of golf -- has changed greatly since his Nov. 27 SUV accident just outside of his Florida driveway.
That mysterious run-in with a fire hydrant and a tree began a stream of negative publicity that continued with numerous reports of marital affairs, his leave from the game, a stint in undisclosed rehab, and a gradual return to the public glare.
Woods said that that he had five stitches in his mouth after the infamous Thanksgiving night car crash.
Woods also said he made "some incredibly bad decisions" and "hurt so many people." He again said that he takes all the blame for allowing his life to fall apart and refused to say why he spent 45 days in rehabilitation. He said he intends to continue with his treatment.
While his wife, Elin, won't be joining him at Augusta, Woods still believes he can win his fifth green jacket after a five-month layoff.
Woods made his first public comments on Feb. 19 at PGA Tour headquarters in Ponte Vedra Beach, Fla., apologizing to his family, friends and business associates and promising to "make amends, and that starts by never repeating the mistakes I've made. It's up to me to start living a life of integrity."
Just less than a month later, on March 16, Woods announced that he would be returning to golf at the Masters. On March 21, he gave his first interviews, five-minutes each to ESPN and Golf Channel. Monday was the first time he took questions in an extended format.
Typically, Woods would have fielded queries in a pre-tournament setting which topics such as why he has not won the Masters in five years or why he has claimed just one green jacket in his past seven attempts.
But after a break from golf of nearly five months, the answers to those questions were left for another day.
Masters officials made it clear that it was their idea for the interview to take place on Monday, not as a concession to Woods, who would have normally met the media on Tuesday. But to do so then would have rendered every other interview meaningless, while making it impossible to get the focus on the tournament.
"A lot has happened in my life in the past five months," Woods said. "I'm here at the Masters to play and compete and I'm really excited about doing that."
Earlier Woods played a practice round with former Masters champion Fred Couples. They were joined by Jim Furyk on the 13th and played the rest of the way together.
Although the crowd was cordial, it was not overly enthusiastic.
Woods made an attempt to interact with spectators -- not typical for him -- and even engaged in the tradition of trying to skip a shot over the pond at Augusta's par-3 16th. Nobody ever remembers Woods doing that.
Written: ESPN Bob Haraig