England’s Luke Donald has undergone tests in hospital for chest pains and will not return to action until 2018.
The former world number one, 39, was entered in this week’s PGA Tour event – the RSM Classic in Sea Island, Georgia.
But he revealed he was taken to South East Georgia Brunswick hospital and he has withdrawn from the competition.
“Chest pain last night and this morning and it kept getting worse,” said Donald. “After seven hours of tests all looks good with my heart thankfully.”
He added: “Time to put my feet up for a few weeks, recharge, regroup and get ready for a big 2018.”
Donald is ranked 123 in the world having started 2017 at 81 and has not won on the PGA Tour since 2012.
He had been due to partner with Brandt Snedeker and Sea Island resident Matt Kuchar for the first two rounds of the RSM Classic.
American Chris Kirk led the tournament by two shots after shooting a nine-under par 63 in his opening round.