Alexander Zverev, Andrey Rublev and Marin Cilic have each tested negative for coronavirus, but will continue to self-isolate and take daily tests.
Two of the pair's fellow players —Borna Coric and Grigor Dimitrov—tested positive for COVID-19 after playing the Novak Djokovic-led Adria Tour.
More: Coric Tests Positive, Kyrgios Rips Adria Tour
Zverev also "deeply apologizes" to anyone he may have potentially put at risk, though he has tested negative.
"I just received the news that my team and I have tested negative for COVID-19," Zverev said in an Instagram post. "I deeply apologize to anyone that I have potentially put at risk by playing this tour.
"I will proceed to follow the self-isolating guidelines advised by doctors. As an added precaution, my team and I will continue with regular testing."
Rublev reported on Twitter he tested negative for the virus and will also self-isolate.
Cilic also plans to self-isolate for 14 days.
Serbian media reports world No. 1 Djokovic headed back to Belgrade for testing with some saying he has tested negative though the 17-time Grand Slam champion has not yet issued a statement on social media.
Photo credit: The Adria Tour