Golf superstar Tiger Woods speaks with a rules official after withdrawing from the Genesis Invitational because of illness (Sean M. Haffey)

Golf superstar Tiger Woods withdrew in the second round of the Genesis Invitational because of illness on Friday in the latest setback for the 15-time major champion.

The US PGA Tour said Woods pulled out after hitting his tee shot at the seventh hole because of illness, with no immediate word on the nature or severity of the trouble.