Dustin Johnson
Johnson has been in fine form leading up to the Masters Reuters

Dustin Johnson has suffered a back injury on the eve of the Masters after falling in his rental home in Augusta on Wednesday (5 April). The American, who was the favourite to earn a green jacket this weekend, is now a major doubt for the Masters and has been told to "remain immobile" and not exacerbate his injury.

Johnson's agent David Winkle revealed that his client is still hoping to play on Thursday and is currently resting ahead of his tee-off time, which is scheduled for 7.03pm. The 32-year-old is in fine form going into one of the biggest events on the golfing calendar having won his last three tournaments, with his most recent success coming in the World Match Play final in March.

"Dustin took a serious fall on a staircase in his Augusta rental home," Winkle said in a statement, relayed by BBC Sport. "He landed very hard on his lower back and is now resting, although quite uncomfortably.

"He has been advised to remain immobile and begin a regimen of anti-inflammatory medication and icing, with the hope of being able to play."

Despite widespread doubts over Johnson's fitness and ability to take part in this year's Masters, his coach Joey Diovisalvi is "optimistic" that he will be able to compete.

Johnson will be the fourth world number-one after Rory McIlroy, Greg Norman and Tiger Woods to miss a major championship if he fails to overcome his knock, but coach Diovisalvi, who has also caddied for the US Open winner, hopes that won't be the case.

"He landed on the left side of his lower back in the muscular area," Diovisalvi told SiriusXM. "You know these things happen, but the good news is that it wasn't a flight of stairs. He's comfortable, we're optimistic but we have to see what happens overnight. He's done such a great job over the last couple of years getting strong, I think that helps."