Eighth-seeded Matteo Berrettini withdrew from Wimbledon on Tuesday after testing positive for COVID-19.
The 26-year-old Italian was the runner-up at the grass-court Grand Slam last year, losing to Novak Djokovic in four sets.
Berrettini, who posted on Instagram that he was "heartbroken" with the development, was scheduled to play his first-round match Tuesday against Chile's Cristian Garin. He was replaced in the field by Sweden's Elias Ymer.
"I have had flu symptoms and been isolating the last few days," Berrettini wrote, in part. "Despite symptoms not being severe, I decided it was important to take another test this morning to protect the health and safety of my fellow competitors and everyone else involved in the tournament.
"I have no words to describe the extreme disappointed (sic) I feel. The dream is over for this year, but I will be back stronger."
Berrettini came to the All England Club with momentum, having won tuneup titles on grass at Stuttgart, Germany, and the Queen's Club in London. Since the start of 2019, he is 32-3 on grass.
Also Tuesday, three-time Grand Slam semifinalist Grigor Dimitrov retired from his first-round match against Steve Johnson with a leg injury. The 18th-seeded Bulgarian won the first set 6-4 and was trailing 5-4 in the second when the action ended.
--Field Level Media