World number five Andrey Rublev is the fifth player to test positive for COVID-19 after playing at an exhibition event in Abu Dhabi this month.
Spaniard Rafael Nadal, Canadian Denis Shapovalov, Switzerland's Olympic champion Belinda Bencic and Tunisian Ons Jabeur all tested positive after taking part in the event.
US Open champion Emma Raducanu tested positive in Abu Dhabi before the event and withdrew, while Nadal's coach Carlos Moya also contracted the novel coronavirus.
The 24-year-old Rublev, who beat Andy Murray in the World Tennis Championship final on December 18, confirmed on Twitter he was isolating with minimal symptoms.
"I am currently in Barcelona and unfortunately tested positive for COVID-19," the Russian said. "I am in isolation and following all the protocols under the supervision of doctors.
"As you know, I am fully vaccinated and was preparing for tournaments – ATP Cup and Australian Open. Now I have to recover and I will go to Melbourne only when it will be safe for everyone."
The Australian Open will be held at Melbourne Park from January 17. Rublev was part of the Russian team that won the men's ATP Cup this year and had been included in the team for the upcoming edition in Sydney, which kicks off on Saturday.
World champions India survived a scare before edging out minnows Japan by two runs in a Twenty20 International that was reduced to five overs per side due to rain on Tuesday.
The governing FIA's Formula One commission has agreed on Monday to reduce the standard Grand Prix distance from 305km to 290km from 2027, cutting races by two or three laps.
The Royal Spanish Football Federation (RFEF) has announced Monday that its board of directors has unanimously approved an extension of coach Luis de la Fuente's contract until 2032.
FIFA President Gianni Infantino proposed an outside review of how the governing body makes major decisions on Monday, acknowledging in a letter to members that its handling of a now-abandoned investment plan had caused concern.
Captain Marquinhos has snatched the winner as champions Paris St Germain won 2-1 at troubled Olympique de Marseille in Ligue 1 on Sunday, condemning the hosts to a fifth successive loss and a spot in the relegation zone.
Sheikh Ahmed bin Rashid Al Maktoum has been laid to rest at Dubai's Umm Hurair Cemetery on Tuesday, following a funeral prayer attended by royals at Grand Zabeel Mosque.
Sheikh Ahmed bin Rashid Al Maktoum has passed away on Monday, with the Court of His Highness Sheikh Mohammed bin Rashid Al Maktoum, Vice President and Prime Minister of the UAE and Ruler of Dubai, declaring a 10-day mourning in the Emirate.