Anthony Kim withdrew from the 50th Bob Hope Classic hosted by Arnold Palmer on Tuesday.
PGA tour officials said Kim's withdrawal was caused by a shoulder injury and more information will be available later in the day.
In a statement from Kim, he said that he need to me cautious.
We don't consider my shoulder to be anything too serious, and I don't expect to miss extended time, but it is important to be cautious with it at this early stage in the season, He said.
Doctors told to Kim that he need to withdraw from the game, Kim had an MRI on his shoulder. Media officials did not know of the results of that MRI or which shoulder was injured.
Kim spent his last few years of high school in the Palm Springs area and considers the Hope his hometown event.
The American twice won on the PGA Tour last season and posted eight top-10 finishes. He won twice last year and was considered an emotional leader in helping the Americans win the Ryder Cup.
Kim is the number nine player in the world golf rankings and tied for third in the Hope last year.
The 90-hole tournament begins on Wednesday.