All eyes will be on Phil Mickelson when the 2021 U.S. Open begins at Torrey Pines on Thursday, with the left-hander seeking the final piece to his career grand slam just down the road from his childhood home in San Diego. 

William Hill Sportsbook lists Jon Rahm as the 10-1 favorite in its latest 2021 U.S. Open odds. He is followed by a group of several top players, including Dustin Johnson (16-1) defending champion Bryson DeChambeau (18-1), Brooks Koepka (18-1), Rory McIlroy (20-1) and Jordan Spieth (20-1). 

Before you lock in any 2021 U.S. Open picks or PGA Tour predictions, you NEED to see who golf insider Sal Johnson is backing.

A media legend and consummate golf insider, Johnson has a strong feel for when a player's momentum will make a difference. Before the Memorial Tournament two weeks ago, the golf expert had Jon Rahm and Collin Morikawa listed among his best bets, citing both as players who were coming in with momentum.

Both were in contention all week, and Rahm had a six-stroke lead at 18 under par following his third round and looked poised to defend his title. Then, the Spaniard received word that his pre-round test had come up positive for COVID-19 and had to withdraw.

That left the door open for Patrick Cantlay and Morikawa, and they battled with clutch putts all day. Both got to 13 under, and it went to overtime, with Cantlay prevailing with a par on the first playoff hole.         

Johnson also knows how the players' games fit the courses. Before Mickelson shocked the golf world in the PGA Championship at Kiawah Island, the golf guru made it a point to include Louis Oosthuizen among his contenders. Johnson told SportsLine that Oosthuizen excels on links-style tracks like the Ocean Course and said he is "always a good pick in majors." 

The South African came in as a 60-1 long shot but was right in the middle of the action all weekend and went 4 under to tie for second. 

The golf guru 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, then touted Tyrrell Hatton before he got 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 U.S. Open picks, and they will surprise you.

Shockingly, Johnson is fading Thomas, even though he won the Players Championship and is the No. 2 player in the world. The 27-year-old has not been playing well outside of his Players win and it doesn't look like his week to bounce back!

Instead, Johnson is touting a MAJOR long shot who comes in at well over 50-1 odds! This veteran has a strong track record at Torrey Pines. This could be his chance to pull off a shocker and win the 2021 U.S. Open! Anyone who backs this underdog could cash in HUGE.

Who wins the 2021 U.S. Open? Where do Bryson DeChambeau and Jon Rahm 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 U.S. Open, all from the insider who has a strong feel for how players' skills fit the courses and which players can keep up their momentum!