Jason Day's Masters campaign is again in doubt after a seeming recurrence of a niggling back injury.
The Australian lost the final two holes of his World Match Play Championship first-round clash with Jim Furyk in Texas today, then immediately sought treatment after visibly being in discomfort for the final 20 minutes of their match.
The latest issue comes three weeks after Day withdrew from the Arnold Palmer Invitational because of pain related to an annular disc tear. He walked off the course after just six holes at that event and received four cortisone injections around his spine that night.
He returned to record a top-10 finish at the Players Championship, but missed the cut at last week's Valspar Championship.
Day, who withdrew from the 2012 Masters during the second round and was also forced to miss the 2016 US PGA Tour playoffs with a back injury, is hell bent on success at Augusta National.
But with the first men's major championship less than two weeks away, he's now in a race against time to be fit.
Day, the 2014 and 2016 WGC-Match Play winner, blew a sizeable lead over American veteran Furyk at the Austin Country Club today.
He built a 3-up advantage only to lose the next three holes with Furyk rattling off a trio of birdies from the 10th hole.
The Queenslander three-putted the 17th to lose the lead before Furyk birdied the 18th with a 3m putt to win 2-up.
"I'm standing on the 9th tee 3-down and kind of trying to figure out what happened, to be honest with you," Furyk said.
"I guess my goal from there on out was just to play solid golf, try to make him earn every hole."
It was mixed day for the Aussies with only Victorian Marc Leishman successful, a 2-up winner over Thailand's Kiradech Aphibarnrat.
Queenslander Cam Smith was 2-up through 12 holes, but made three bogeys in his next four holes to enable American Charles Howell to win 2&1.