Even with the PGA Tour starting a new season in October, and big golf being played around the world, Tiger Woods said he was pleasantly surprised to draw another big cast of stars to his holiday tournament in California.

“It’s our deepest and strongest field that we’ve had, possibly ever,” Woods said Tuesday.

The World Challenge has not announced its two sponsor exemptions from among the top 50 in the world ranking to fill out the 18-man field. The tournament, which was in jeopardy this summer until Northwestern Mutual stepped in as a title sponsor, will be held Dec. 5-8 at Sherwood Country Club.

It includes defending champion Graeme McDowell, along with three other Europeans who will be competing in Asia for the Race to Dubai in the weeks leading up to Woods’ event. Rory McIlroy, Lee Westwood and Ian Poulter are expected to play.

Ernie Els is playing the World Challenge for the first time. Jason Day returns, though the Australian is making a rare trip Down Under this year to compete in World Cup at Royal Melbourne just two weeks before Woods’ tournament.

The other Americans besides Woods are PGA champion Jason Dufner, Matt Kuchar, Hunter Mahan, Brandt Snedeker, Zach Johnson, Bubba Watson, Jim Furyk, Keegan Bradley and Steve Stricker.

“I think we’re all very surprised that we’ve got as many international players playing this year,” Woods said during a conference call. “The American players have supported our event throughout the years. Obviously, it’s easier travel if you’re based in the States. The guys who are playing in the Race to Dubai, it’s a bit more of a challenge to get them to play. But for some reason, this year we’ve had guys wanting to play and we have probably the best field we’ve had.”

The tournament will be played for the 15th time, and it means so much to Woods that last year he invested his own money — believed to be about $4 million — to help cover operating expenses and to make sure there would be enough proceeds to benefit his foundation.

One challenge this year was the new wraparound season on the PGA Tour, starting in October and ending with the Tour Championship next September. There are six tournaments the rest of this fall — two in Asia — that offer full FedEx Cup points and official money.

Woods’ tournament is not official. It counts only toward the world ranking. And the total purse ($3.5 million) is smaller than any tournament on the PGA Tour or European Tour for the rest of 2013. That didn’t seem to matter.

“I think word has spread,” Woods said. “We’ve always treated players well there. They’ve had a great time. It’s close enough to the following year where some of the guys want to try and experiment with a few things equipmentwise, club deal. They want to get a tournament in before they play Kapalua, the Hawaiian Open. Some of the guys have done that in the past.

“Otherwise, we’ve had great American support,” Woods said. “But it’s pretty incredible to get the international support we’ve gotten this year.”

Woods has only two tournaments remaining in 2013 — Turkey and the World Challenge.

Woods still hasn’t adjusted to the notion that a new season already is underway.

“Some of the players were talking about that at the Presidents Cup,” he said. “It’s hard to believe the very next week is a tour event. We felt like we were still playing our season because we were still playing The Presidents Cup. I think it’s going to take a little bit of time to get accustomed to it.”