Pain keeping Tiger muted

Back spasms not only kept Tiger Woods from playing at Riviera, they forced him to withdraw from a media conference on Wednesday.

Woods, the unofficial host of the Genesis Open, said in a statement that, after getting daily treatment over the last four days, he was advised by doctors to limit all activities.

"He flew out here and got to see one of his doctors," Mark Steinberg, Woods' agent at Excel Sports, said on Wednesday.