Vonn tore her anterior cruciate and medial collateral ligaments last week during the super-G in Schladming, Austria. She also broke a bone in her lower leg.
Sterett said it was too early to issue a specific prognosis and didn't have a return date to skiing for Vonn. But other doctors believe she could be sidelined for up to eight months.
That would give her time to get back to the slopes for the 2014 Sochi Winter Games, which are a year away.
• Marion Rolland of France beat all the favorites to win the world downhill title Sunday, mastering an icy course that left most of her rivals struggling to find the right race line in Schladming.
Rolland, who has yet to win a World Cup race after 15 top-10 finishes in downhill, earned her first medal at a major championship after charging down the 1.9-mile Streicher course in 1 minute, 50.00 seconds. Nadia Fanchini of Italy took second place, 0.16 seconds back. The downhill was the first of the season in which an American didn't reach the podium.
Olympic champion Ireen Wust beat Dutch teammate Diane Valkenburg for the second time in two days to win the 3,000-meter race at a speedskating World Cup meet in Inzel, Germany.
Wust and Valkenburg also finished 1-2 in the 1,500 a day earlier. Wust, dominated Sunday's race, winning by 3.08 seconds.
Denis Yuskov of Russia edged World Cup leader Zbigniew Brodka of Poland by 0.02 seconds to take the men's 1,500 in a close race. Brian Hansen of the U.S. was third, 0.07 seconds behind.
Sara Takanashi of Japan moved closer to winning the women's ski jump world title by sweeping a World Cup doubleheader in Yamagata, Japan.
The 16-year-old Takanashi has a 230-point lead in the overall standings over defending champion Sarah Hendrickson of the United States with four events left and could wrap up the title in Slovenia next weekend.