Woods appeared Wednesday to help publicize the Chevron World Classic, an exhibition tournament he hosts each year at the Sherwood Country Club.
Despite suffering from ligament damage in the knee, Woods played in and won the 2008 U.S. Open in dramatic fashion -- defeating Rocco Mediate in a playoff that went 19 holes.
"The legs are strong. I'm still in the healing process," Woods said. "I can't tell you when (he will return to action). My surgeons can't tell you when. There's some uncertainty in how it (the knee) is going to respond.
"Everyone heals at different rates. I learn to live with it day-by-day."
The U.S. Open title was the 14th major championship of Woods' career. He needs four more to tie the career record held by Jack Nicklaus. The first major event of 2009 will be the Masters in April.
Woods also said he considered the controversy stirred up by his caddie Steve Williams last week to be "over and done with."
Williams had several derogatory things to say in New Zealand newspapers about a Woods' rival, Phil Mickelson.
"I communicated with Phil and we discussed it," Woods said. "I talked to Steve and he feels badly about it."