Swiss tennis star Roger Federer has left his latest comeback date open but insisted on Wednesday that he wants to return to the ATP Tour. “I can still not run. But I’m working daily in the gym,” the 40-year-old Federer said at a sponsor’s event. “I really hope that I can put weight on my knee again in two to three weeks. “Then we’ll see how the body reacts so we can hit the ball again in April or May.” The long-time former men’s world number one had a third knee surgery last August and has not played since a quarter-final loss at Wimbledon in 2021. “Of course I wish that everything could go qu…