ATLANTA — Louis Oosthuizen of South Africa withdrew from the elite Tour Championship after 13 holes of Thursday's first round because of a hamstring injury, and was concerned about his readiness for the upcoming Presidents Cup.
Oosthuizen, the 2010 British Open champion, was five over par when he was carted off at East Lake Golf Club.
The 32-year-old South African, who also had his wrist drained on Wednesday to treat a cyst, said he had been bothered by the hamstring earlier in the week but felt fine at the beginning of the opening round.
"Starting the round I didn't even feel it, I didn't even know about it," he said.