Danny Willett admitted he needs to rest his "mind and body" after pulling out of The Players Championship midway through the second round.
Willett's career has been blighted by back injuries, and the problem flared up again at TPC Sawgrass as he completed only nine holes on day two before heading for the clubhouse.
The Englishman needed something in the mid-60s to make the cut after opening with a 79, but he began his second round with a bogey at the 10th although he rebounded with a birdie at 11.
But last year's Masters champion again found water at the 17th and ran up a triple-bogey six, and he shook hands with his playing partners after a par at the closing hole after deciding he could not continue.
Willett remains without a victory since his memorable win at Augusta National, and he has been undergoing swing changes with coach Pete Cowen in an attempt to alleviate his troublesome back problems.
Shortly after his withdrawal, he tweeted: "Not good to have to withdraw but swinging very poorly is putting a lot of unwanted strain on the back. Body and mind need a rest!!"
Meanwhile, Willett's fellow Englishmen Matt Fitzpatrick and Ross Fisher also made an early exit from the tournament after both followed opening round of 76 with 73s which left them comfortably outside the cut mark on five over par.
Ireland's Shane Lowry, who was playing alongside Willett, also crashed out after completing a disappointing 76 with a double-bogey seven at the ninth to plummet to six over.
But Olympic champion and Masters runner-up Justin Rose survived the cut as he battled to a one-under 71 to post a 36-hole score of one over, a score matched by Lee Westwood despite the veteran labouring home in 40 to card a disappointing 75.
Two-time Masters winner Bubba Watson's slump continues as he bowed out on seven over after rounds of 76 and 75, which included visits to the water at both 17 and 18 as he dropped five shots in two holes.
Another former Augusta champion, Charl Schwartzel, was another major winner to have the weekend off along with his fellow South African Ernie Els, with both slumping to six over par.