Matteo Berrettini was on a nine-match winning streak coming into Wimbledon having won both Stuttgart and Queen's and was one of the favourites for this year's title after reaching the final last year but has tested positive for COVID-19 ending his hopes.
Berrettini took to social media to announce the news and said that despite his symptoms not being severe, he took another test to protect others which came back positive.
Elias Ymer replaces Berrettini and will face Garin. The Italian becomes the second name in recent days to withdraw due to COVID-19 with Marin Cilic falling yesterday.
"I am heartbroken to announce that I need to withdraw from @wimbledon due to a positive COVID-19 test result. I have had flu symptoms and been isolating the last few days," he wrote on Instagram.
"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 disappointment I feel. The dream is over for this year, but I will be back stronger.