Title favourite Dustin Johnson threw a late spanner in the works on the eve of the 81st Masters after hurting his back in a “serious fall”.
The world No 1 suffered the injury as he slipped walking in socks on a barewood floor at his rented house in Augusta.
“At roughly 3pm today, Dustin took a serious fall on a staircase in his Augusta rental home,” his agent, David Winkle, revealed in a statement.
“He landed very hard on his lower back and is now resting, although quite uncomfortably.”
Winkle added: “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 tomorrow.”
It was later reported that Johnson, who has won his last three events, had been left “shaken up” by the fall, which saw him land on his lower back and both elbows.
The injury was described as “muscular in nature” and is being treated by a mixture of ice, heat and compression tape.
His team will “re-evaluate” the situation in the morning, though he does at least have the advantage of being in the final group out in the first round at 2:03pm local time.