Lindsey Vonn will not be able to defend her downhill Olympic gold medal at the upcoming Sochi Games due to an injured knee.

In a statement released early Tuesday, the 29-year-old girlfriend of world top-ranked golfer Tiger Woods also announced she is "devastated" by the news. "I did everything I possibly could to somehow get strong enough to overcome having no ACL but the reality has sunk in that my knee is just too unstable to compete at this level," she added. "I'm having surgery soon so that I can be ready for the World Championships at home in Vail next February."

Vonn added that she will need another knee operation but that she hopes to be ready for the 2015 World Championships.Vonn underwent surgery early last year to reconstruct two knee ligaments after a crash at the world championships, and partially re-tore one of them in November. She returned to the World Cup in Lake Louise, Alberta, during the first week of December and finished 40th and 11th in two downhills and fifth in a super-G event the next day before a loss of balance on the slopes in France later that month effectively ended her comeback effort.

"On a positive note, this means there will be an additional spot so that one of my teammates can go for gold," Vonn later added. "Thank you all so much for all of the love and support. I will be cheering for all of the Olympians and especially team USA!"

Vonn won two medals at the 2010 Vancouver Olympics, including a gold in the downhill. She is also a four-time overall World Cup champion and the biggest name in Alpine skiing.