The biggest golf tournament of the year that's not officially recognized as a Major Championship is underway.

The Players Championship, often described as the Fifth Major, began Thursday morning. The event is being held TPC Sawgrass in Ponte Vedra Beach, Florida. John Mallinger, Cameron Tringale and Lakde Adams got things started at 7:15 a.m. ET.

After recently taking over the world number one ranking, Rory McIlroy is the favorite to win the tournament. The online sportsbook Bovada puts his odds of winning at 9/1. Lee Westwood has the second best odds, according to the site. The player who's been battling McIlroy for the top spot is 14/1.

McIlroy is expected to tee off at 1:49 p.m. ET, while Westwood starts 10 minutes before him.

Despite his poor showing at the masters a month ago, Tiger Woods has the fourth best odds to win the Players Championship. He comes in at 20/1.

K.J. Choi won the event a year ago. He's not expected to win, with his odds set at 80/1 of taking home the title for a second straight year.

A complete leaderboard for the event can be seen here.