European Ryder Cup star Paul Casey withdrew from the BMW Championship on Monday due to a back problem.
The Englishman was selected as a captain's pick last week by Thomas Bjorn, having missed out on automatic qualification for this month's competition.
But there was cause for concern for Team Europe in Philadelphia as Casey pulled out of the third FedEx Cup Playoff event ahead of the fourth round belatedly getting under way on Monday.
Casey was still in line to play the Tour Championship when his participation at the BMW was halted, sitting in a projected 26th place in the FedEx Cup standings as 30 progress.
A further weather delay preventing more than half of the field from completing their rounds on Monday would see the event called over after 54 holes, with the projected 30 heading through.
