UNIONDALE, N.Y. — Defending champion Kevin Anderson has withdrawn from the New York Open because of a right elbow injury.

Frances Tiafoe, the American who reached the Australian Open quarterfinals before falling to runner-up Rafael Nadal, was added to the field Thursday. The tournament begins Sunday.

Anderson, ranked fifth, was hurt during last month's Grand Slam tournament in Australia. He was runner-up last year at Wimbledon and says his victory on Long Island "kick-started my year in 2018 and I was very excited to return."

His withdrawal leaves American John Isner as the highest-ranked player in the field at No. 9. Anderson outlasted Isner in a marathon semifinal at Wimbledon.

Australian Alex de Minaur, last year's ATP top rookie, also pulled out of the tournament because of an injury.