The absence of Tiger Woods from the PGA Tour has dealt professional golf a major blow and the game needs the world No 1 back in action, second-ranked Phil Mickelson said on Wednesday.

Woods, the sport's most bankable player, has been in hiding since admitting last month he had cheated on his wife and he has given no indication as to when he will return to competition.

"The game of golf needs him to come back," Mickelson saidy while preparing for Thursday's opening round of the San Diego Open.

"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 (his wife) Elin and we care deeply about how this turns out," said Mickelson, who is launching his 2010 PGA Tour campaign this week.

"But I'm going to choose not to talk about it publicly any more ... we're friends and we have a personal relationship. I feel like it's a violation of our trust and our relationship."

Asked if he had spoken to Woods since his personal life unraveled amidst tawdry revelations about extra-marital affairs, Mickelson said: "We've had limited communication with the Woodses.

"Again, I just feel like discussing any of that is just not appropriate."

In the absence of Woods for at least the first part of this season, many pundits believe three-time major champion Mickelson has a responsibility to fill the void.

"I haven't thought about it like that," the American world No 2 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.

"But this year, whether or not Tiger is in the field, I believe is an opportunity for me to compete in majors."

Mickelson, one of the game's most gifted shotmakers, has every reason to hold great expectations after ending 2009 in barnstorming fashion.

He clinched the PGA Tour's season-ending Tour Championship in September and the WGC-HSBC Champions in China in November after overshadowing Woods in each of those high-profile events.

"First of all, I feel ready but second, at the end of last year, I felt like things were starting to really come together," Mickelson, 39, said.

"Taking some weaknesses and turning them into strengths gives me the confidence and the belief that this could be an exceptional year."