U.S. No. 1 and 13th-ranked John Isner withdrew from the Australian Open because of a bone bruise in his right knee.
The Australian Open Twitter account tweeted the announcement along with some quotes from Isner himself.
Isner has struggled with the knee injury since the beginning of the year, withdrawing from his third match at Hopman Cup last week. He continued to try to play through the pain this week in Sydney, where he lost his opening match to fellow American Ryan Harrison 6-4, 6-4. Asked about his injury after that match, Isner admitted he was doubtful for Melbourne.
“From now up until Melbourne I definitely can’t practice like I need to,” he said. “I could play. Certainly I could win a match maybe, a match or two. I don’t see myself winning the whole tournament at this point, that’s for sure.” Isner's withdrawal means Sam Querrey will be the only seeded American when the tournament begins on Monday.