PACIFIC PALISADES, Calif. -- Tiger Woods withdrew from the second round of the Genesis Invitational on Friday because of illness, the PGA Tour said.

Woods pulled out of the tournament after hitting his tee shot on the seventh hole at Riviera Country Club. He was taken off the course in a golf cart driven by a tournament official. At one point, Woods put his head in his hands in frustration.

Woods battled back spasms in Thursday's opening round and seemed to be having issues with his back again Friday. The 15-time major champion has undergone five back surgeries during his career.

Woods was making his first start in an official PGA Tour event since he withdrew from the rain-delayed third round at the Masters in April.

Woods, 47, was 1 over after six holes in the second round. He was 2 over for the tournament, which he hosts.