Byeong Hun An withdrew from the Travelers Championship during the first round on Thursday due to illness, according to PGA Tour Communications.
He completed the first seven holes and was 1-over before heading to the clubhouse.
An, 32, was paired with Sam Burns for the first round at TPC River Highlands in Cromwell, Conn.
An, ranked No. 27 in the Official World Golf Ranking, is scheduled to represent South Korea in the Summer Olympics. He has five top-10 finishes this season.