The Austrian is likely to be in a cast for the next six weeks.

However, his doctor Gerhard Oberthaler estimates he will need up to 15 weeks to recover fully.

"If you have been in a cast for six weeks, your ankle is not immediately ready for ski training," Oberthaler told the Austria Press Agency.

Hirscher, the winner of a record six consecutive overall World Cup titles, is set to miss the season-opening giant slalom in Soelden in Austria on October 29.

A start in the slalom race scheduled for November 12 in Levi in Finland is also doubtful.

The next set of technical races are due to be held in Val d'Isere in France on December 9 and 10.

Hirscher sustained a fracture on the lateral malleolus of his left ankle after straddling a slalom gate on the Mölltaler Glacier in Austria and crashing.  

He was taken by helicopter to University Hospital Salzburg, where the fracture was diagnosed.

It was Hirscher’s first on-snow training of the season, which includes the Pyeongchang 2018 Winter Olympic Games in February.

The 28-year-old has won nine medals at the International Ski Federation Alpine World Ski Championships, including six golds.

He claimed a silver medal in slalom at the 2014 Winter Olympics in Sochi.