Jason Day has withdrawn from the Arnold Palmer Invitational after being troubled by a back problem during the second round.
The 32-year-old Australian, who had shot a two-over 74 in the first round at Bay Hill, was playing the fifth hole when he decided to return to the clubhouse in a buggy.
It is the second successive year Day, who appeared to be walking with a limp, has pulled out of the tournament with back issues after only lasting six holes last year.
Day, who won the Arnold Palmer Invitational in 2016, has been plagued by a back problem for some time but said ahead of the tournament the injury was under control.
He had been restricted to no more than 30 minutes of putting practice at a time earlier this year but had increased that ahead of a busy spell in the calendar, with the Masters coming up next month.
"My back is much better and we're coming into warm Florida weather, which helps," Day told the Sydney Morning Herald on Tuesday.
"I'm now putting for an hour and a half, only 30 minutes or so less than what I normally do."