In-form Will Zalatoris withdrew during the US PGA Tour’s BMW Championship on Saturday.
Zalatoris, who ended his long wait for a tour victory by winning last week’s St Jude Championship in a playoff, suffered a back injury on the 4th hole of the third round.
The 26-year-old, the current leader in FedEx Cup playoff points, received treatment after playing his second shot.
Zalatoris had started the third round at Wilmington Country Club five shots adrift of leader Adam Scott.
© Agence France-Presse