Bulgaria's Grigor Dimitrov, who played in both of Novak Djokovic's recent Adria Tour events, says he has tested positive for coronavirus.
Dimitrov, 29, withdrew from the second tournament in Zadar, Croatia on Saturday with sickness after his opening loss to Borna Coric.
In a statement on Instagram, Dimitrov wrote: "I am so sorry for any harm I might have caused."
He added: "I tested positive back in Monaco for Covid-19. I want to make sure anyone who has been in contact with me during these past days gets tested and takes the necessary precautions.