Olympic downhill champion Lindsey Vonn re-injured her surgically repaired right knee in a Colorado training crash ahead of her return to racing.
The 29-year-old American partially tore the right anterior cruciate ligament that she injured in February.
US Ski Team medical staff did not put a date on her comeback, saying "her response to therapy will determine the timetable for her return".
The women's downhill at Sochi 2014 will take place on 12 February.
Lindsey Vonn factfile
Makes World Cup debut aged 16 in Park City, Utah
Competes at Winter Olympics in Utah aged 17 in downhill and combined
Claims first World Cup race win at Lake Louise in Canada
Wins first World Cup title to become only the second American woman to lift the trophy
Wins World Championships in Val-d'Isere, France, and becomes first American to win women's world Super-G title
Wins downhill gold at Winter Olympics
Vonn also suffered a mild strain to the knee and cuts to her face and shoulder in the accident at the Copper Mountain resort.
"She plans to rest for a few days before pursuing physical therapy," added US Ski Team spokesman Tom Kelly.
The injury is likely to scupper Vonn's planned comeback at the World Cup event in Beaver Creek at the end of November. It could also put in doubt her bid to
defend her Olympic crown
at Sochi in February.
The four-time overall World Cup champion only
started training in September
after being out for seven months with ruptured ligaments following a crash at the
in Schladming, Austria.
Vonn's friend and team-mate Julia Mancuso
tweeted on Tuesday:
"Let's all send Lindsey Vonn our positivity and hope for the best."
The American is dating 14-time major golf champion Tiger Woods.