The subject of COVID-19 vaccines continues to weigh on some of the tennis' biggest stars. World No. 3 Stefanos Tsitsipas told reporters he isn't planning to get vaccinated unless the ATP Tour mandates it. "No one has told me anything. No one has made it a mandatory thing to be vaccinated," the 23-year-old Greek said Monday in Cincinnati at the Masters 1000 Western Southern Open tournament. "At some point I will have t