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Tiger Woods hasn't been this busy on the golf course in seven years, a season that will wrap up in California with his annual World Challenge.

Still to be determined is whether he'll keep playing that many events.

On Wednesday, Woods announced the 18-man field for the World Challenge, to be played the week after Thanksgiving at Sherwood Country Club. Woods is the defending champion, outlasting Zach Johnson to end a two-year drought.

The field features 13 players from the Ryder Cup — all but Phil Mickelson from the United States, only Graeme McDowell and Ian Poulter from Europe — along with Hunter Mahan, Nick Watney, Bo Van Pelt, Rickie Fowler and Jason Day. All of them are among the top 30 in the world.

For Woods, the World Challenge will be his 24th tournament of the year, which includes the Ryder Cup and the exhibition he played last week in Turkey. That's his busiest schedule since he played 25 times in 2005, not including the Skins Game and PGA Grand Slam of Golf.

"It was nice to be able to — other than one setback at Doral this year — to be healthy enough to where I have the opportunity to play as much as little as I want," Woods said in a conference call. "It wasn't something I was forced to sit on the sidelines, forced to rehab and get myself back into a position where I can compete. I was able to compete and play as many tournaments as I wanted to. So that was a positive.

"We'll see going forward what that holds."

Woods added four tournaments to his 2012 season that he had never played as a pro — Abu Dhabi on the European Tour, the Honda Classic, the Greenbrier Classic and the CIMB Classic next week in Malaysia, which is unofficial.

In his last full season — without coping with injury or chaos in his personal life — he played 20 times in 2009.

Woods appeared to downplay the notion that he would consider taking up membership on the European Tour. The European Tour is expected to start counting the Ryder Cup (and Presidents Cup) toward the minimum 13 tournaments required. Woods, in response to a question last week in Turkey, said he would look into it.

Luke Donald last year became the first player to win the money title on both tours in the same season, and Rory McIlroy is poised to win both titles this year. Woods would have won the European Tour money title multiple times except that he wasn't a member and didn't play the minimum events, which at the time was 11.

"They asked me the question whether or not I would entertain it, and I said, 'Yeah, I entertained it early on in my career,' because at the time there was only 11 events ... and I played once or twice in Europe, and that put me at nine or 10. Now it's at 13 — 13 is a little bit more difficult to get to, but that's one of the reasons why I think they implemented the Ryder Cup and the Presidents Cup as events that count towards that number.

"I certainly can see the benefits and also see the negatives of playing that much golf," he said. "But going forward, I don't know."

The Abu Dhabi Championship announced earlier Wednesday that Woods and McIlroy will headline the field next January. It was held this year the same week as Torrey Pines, and Woods missed the San Diego event for the first time since 1997 when he was healthy. Next year, Torrey Pines is the week after Abu Dhabi.

Woods didn't rule out playing Torrey Pines, but said he won't map out a schedule until after the World Challenge.

"I'm going to sit down over my offseason and before the new year for sure and plan out everything and see how many events I'm going to play in and whether this year was a good amount, I can play more, I can play less, travel more, travel less and really get a good balance and really analyze what I need to do or what I want to do," he said.

The World Challenge is without a title sponsor for the first time since it began 13 years ago. The tournament said Northwestern Mutual, a longtime supporter of the Tiger Woods Foundation, has stepped in as the presenting sponsor, which should defray some of the operating costs.

The tournament is not official, although it began awarding world ranking points in 2010.