Mickelson didn't wait for questions about Woods. He began a pre-tournament news conference Wednesday at Torrey Pines by addressing the issue of Woods' absence.
"The game of golf needs him to come back," Mickelson said of his longtime rival. "I mean, it's important for him to come back and be a part of the sport. But right now he's got a lot more important things going on in his life.
"Amy and I are good friends with both Tiger and Elin, and we care deeply about how this turns out. But I'm going to choose not to talk about it publicly anymore, and I appreciate your understanding on that."
Woods has not appeared in public since the Nov. 27 accident and has taken an indefinite leave of absence from the game he has dominated over the last decade.
Mickelson, 39, who is ranked No. 2 in the world and makes his debut at the Farmers Insurance Open with high hopes for a big year after finishing strong in 2009, later said he has had "limited communication with the [Woods] family" and that "I don't want to talk about it publicly for the reason that we're friends and we have a personal relationship, and I just don't feel ... I feel like it's a violation of our trust and our relationship."
Mickelson won three times on the PGA Tour in 2009 despite a trying year in which both his wife, Amy, and mother, Mary, were diagnosed with breast cancer.
He finished the season with a victory at the Tour Championship, then won the unofficial World Golf Championship event in China, the HSBC Champions. At both tournaments, he defeated Woods, the No. 1-ranked player in the world.
But Mickelson doesn't see it as his responsibility to fill the void left by Woods' absence.
"I haven't thought about it like that," he said. "I'm just excited to play golf. I'm excited to get back into competition and be a part of this.
"Nobody will be able to fill the shoes that are voided right now. My whole career I've been trying to get to No. 1, I just haven't had much success," he said. "But this year, whether or not Tiger is in the field, I believe is an opportunity for me to compete in majors."
Although Mickelson said the prognosis for both his wife and mother is excellent -- they just returned from where they underwent treatment on Monday and Tuesday -- he also said the medical situation could cause some disruptions in his 2010 schedule.
One will occur in a few weeks, when Mickelson said he will skip the WGC-Accenture Match Play Championship to spend time with his family.
"I expect this to kind of happen a little bit throughout the year, maybe missing tournaments I would like to play or normally would play," Mickelson said. "But later on in the year I'll probably add a tournament that I hadn't originally planned on playing to kind of offset it."
His plan now is to play this week, next week's Northern Trust Open in Los Angeles, where he is the defending champion, and then the AT&T Pebble Beach Pro-Am before taking the week of the Match Play off and then returning for the Phoenix Open.
"I'm excited to get the year started," he said.
Bob Harig covers golf for ESPN.com. Information from Reuters was used in this report.