Alexander Zverev has arrived in his home city of Hamburg but will only decide after first training sessions whether he will participate in the ATP tournament there next week. Zverev damaged his knee last week at Wimbledon, and while the injury is not serious he will not want to take any risks a fortnight before the start of the Olympic tournament in Paris where he aims for back-to-back gold medals. “I trained for two hours today without painkillers,” the Hamburg title holder said in a news conference on Saturday. For comparison, in London, he “shot himself up with painkillers to the limit,” he…