FedEx Cup runner-up Webb Simpson and 2011 PGA Championship winner Keegan Bradley lead the field at the 23rd annual Shark Shootout beginning Friday at Tiburon Golf Club.

Bradley is partnering with Brendan Steele in the challenge-season event featuring 12 two-man teams playing modified alternate shot, better ball, and scramble over three rounds.

Earlier this year, Steele won the Valero Texas Open, and was having dinner with Bradley and their agent. They both asked their agent if they could get in the Shootout. Then Bradley went out and won the Byron Nelson, and the PGA. That made it pretty easy.

"We've texted each other a bunch about (the Shootout)," Bradley said. "We're really excited to get out there and play. We're going to treat this as serious as anything and try to win."

Said Steele: "We're not here to goof off. It's a fun week for everybody, and we're really going to enjoy ourselves, but we want to come in and at least contend for this thing."

Simpson, who finished second on the money list, will team with Anthony Kim — the two played against each other as kids. Other notable teams include Rickie Fowler and Camilo Villegas, 2009 champions Jerry Kelly and Steve Stricker, and 2011 PGA Championship runner-up Jason Dufner and Sean O'Hair.

"We're both competitors, and we want to win the tournament, so hopefully Sunday, we'll be sitting there in contention and try to win," Simpson said.

"He's an easygoing guy," Kim said of his partner. "We both like to joke around and give each other a hard time, and hopefully we can keep that up and make some birdies along the way."

Tournament founder and host Greg Norman is playing with Scott McCarron, who is replacing Fredrik Jacobson. He withdrew after suffering torn ligaments in his left thumb.

Norman has had a busy few weeks. He was the captain of the International team in the Presidents Cup last month in Australia, then played in the Australian PGA, and his design team is one of the finalists to lay out the first course for golf in the 2016 Olympics in Brazil.

"I didn't feel like I played particularly well, but I knew how to play the game," said Norman, who had a pair of 69s and tied for 23rd at the Australian PGA. "I figured out how to get the ball around the golf course, and that put me in a position. I enjoyed it, no question about it. I enjoyed putting myself up there and playing against the younger guys, and actually doing better."

For the first time in its history, the Shootout does not have its defending champions playing.

Dustin Johnson and Ian Poulter won last year, but Johnson had a scheduling conflict with a friend's wedding, and Poulter is playing in the European Tour's event in Dubai.

Johnson had surgery on his right knee to repair cartilage on Nov. 29, and could not have played anyway.