Winter Olympic champion Lindsey Vonn was injured during a downhill training run at Copper Mountain.
Vonn was taken to nearby Vail to be examined by orthopedic surgeon Bill Sterett, who last February performed the right knee ligament repairs on her, reports Xinhua.
Vonn had just come back from months of rehabilitation and doctors need 24 hours before they decide whether the injury would threaten the four-time overall World Cup winner's bid for 2014 Sochi Olympics.
Next week's World Cup event at Beaver Creek includes downhill training Nov 26-28 and the season's first women's downhill race Nov 29.