Cavendish first noticed the problem with his right ankle on the last stage of Tirreno-Adriatico, with team doctors calling it an "overuse" injury. After that race he rode Milan-San Remo.
In a press release, team doctor Jarrad Van Zuydam said, "The injury was thought to be resolving but has unfortunately flared up again during training. Further investigation and treatment is necessary over the coming days to resolve the injury before Mark returns to racing."
He added that even with a speedy recovery it would be premature to set a date for Cavendish's return to racing at this stage. "Cavendish's season is focused on the Tour de France, where he has won a career total of 30 stages."
"The goal is to ensure he is in peak condition come July. With this goal in mind and as a precautionary measure, our African Team will alter Cavendish's race program accordingly so that a full recovery can take place before returning to action."
Cavendish had also been due to ride Wednesday's Scheldeprijs, but was taken off the provisional start list this week. Dimension Data directeur sportif Roger Hammond told Cyclingnews that the team was not prepared to put Cavendish in the race while not at full health. "We're preparing Mark for the focusses that he has and that's why his programme changes," Hammond told Cyclingnews. "We have the prerogative to change things if we don’t think it is right because he comes to win, he doesn't ride from A to B so if he's not 100 per cent healthy then what's the point. He's not here to carry the bottles from start to finish."