Rafael Nadal and Novak Djokovic can relax as rival's injury comeback remains uncertain

Alexander Zverev has revealed that he still doesn't know when he'll return to the tour following his horror French Open injury, in what will come as a relief to Rafael Nadal and Novak Djokovic. The world No 2 has long been touted as one of the threats to their dominance but it seems he will have to wait to be able to challenge them for the big titles again as he remains sidelined.

Zverev was three hours into his French Open semi-final against Rafael Nadal and about to begin a third set tiebreak when he went down on his ankle screaming in pain, and had to be taken off court in a wheelchair. He re-emerged on crutches to retire the match and hasn't been seen on a tennis court since after confirming he underwent surgery after tearing several ligaments.

The German's original plan was to be back in time for the US Open and North American hard court swing but in a new injury update he has confessed that he has no idea when he will be making his comeback - something that will be welcome news to Nadal and Djokovic. "The healing process is going very well," he told Eurosport.

"I'm making important progress every day and I'm looking forward to the next tasks that will bring me closer and closer to the tennis court. An exact date for a comeback hasn't been set yet, but I'm working every day to make sure it happens as soon as possible."

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Opening up on the process of his recovery, he continued: "The days are very long. You start very early and finish in the evening. We do a lot of exercises, there are always new ones that are added permanently.

"The foot is treated, mobility is worked out, strength and stability are rebuilt. In some cases, normal walking