A strong field headlined by top-ranked Dustin Johnson and defending champion Webb Simpson tees off Thursday at the 2021 RBC Heritage at Harbour Town Golf Links in Hilton Head, Island, S.C. 

Johnson is the 10-1 favorite in the latest 2021 RBC Heritage odds from William Hill Sportsbook, followed by Simpson (12-1) and Patrick Cantlay (16-1). 

Before you lock in any 2021 RBC Heritage picks, you HAVE TO see who Sal Johnson is backing.

A media legend and consummate golf insider, Johnson has a strong feel for what it takes to win at Harbour Town. Before last year's event, he had Simpson among his contenders despite the former U.S. Open champ coming in off a missed cut. 

"Stunned a lot of folks with missed cut last week at Charles Schwab," Johnson said at the time. "Still has played well at Harbour Town." Simpson had finished in the top 20 six previous times on the course, and Johnson expected more success. 

The result? Simpson set the tournament scoring record at 22 under, shooting 7-under 64 in the final round to hold off a stern challenge from Abraham Ancer and win by a stroke.   

Before Hideki Matsuyama won last week's Masters, Johnson made special mention of Jordan Spieth, Xander Schauffele and Will Zalatoris as golfers to watch. 

He listed Spieth and Schauffele in his top three contenders and had Zalatoris as his top rookie. Zalatoris nearly caught Matsuyama and finished as runner-up, while Spieth and Schauffele tied for third. 

The golf expert knows these players and how they fit the courses. At the Arnold Palmer Invitational last month, he pegged Bryson DeChambeau as his top choice to win before his second victory of the year.  

He also knows when surging players are poised for a breakthrough. He tabbed Sungjae Im as a top contender before his first Tour win at the Honda Classic last season before touting Tyrrell Hatton to get his first tour victory the following week. Anyone who has followed Johnson's advice has cashed in HUGE.

Now Johnson, the first producer of "Inside the PGA Tour," a longtime ABC Sports golf producer who worked with Jack Nicklaus, Arnold Palmer and Greg Norman, and the founder of the world's top golf stats database, has released his highly confident 2021 RBC Heritage picks, and they will surprise you.

We can tell you the golf expert is fading favorite Dustin Johnson! The South Carolina native comes in at 10-1, but he has been out of sorts (or disinterested) since February, and he missed the cut last week in failing to defend his Masters title. The two-time major champion has shot 73 or worse in six of his past 10 rounds and was T-48, T-54 in the two full-field events before getting to Augusta. There are several better options in the 2021 RBC Heritage field.

Instead, Johnson says you should keep an eye on a MONSTER long shot who has odds higher than 80-1! This golfer has played extremely well at Harbour Town and other courses where shot-making is rewarded. Anyone who backs this underdog could cash in BIG!

Who wins the 2021 RBC Heritage? Where do Webb Simpson and Patrick Cantlay finish? And which MONSTER long shot is a MUST-BACK? ... Join SportsLine now to see Sal Johnson's full leaderboard and picks for the 2021 RBC Heritage, all from the insider who has a strong feel for how to win at Harbour Town!