Tony Olin wasn't altogether surprised to hear that his former pupil, Lindsey Vonn, will not ski in the upcoming Winter Olympics. Olin, who coached the Burnsville native when she was a preteen prodigy, has skied with a brace supporting a surgically repaired knee — and he knows the extreme stress placed on that joint while roaring down a mountain.

Still, given Vonn's record of pushing through injury, Olin expected to see her competing in Sochi, Russia. The defending Olympic downhill champion officially bowed out Tuesday, announcing via a Facebook post that her damaged right knee cannot withstand the rigors of racing. "I really thought she'd be able to keep it together with a good knee brace and accomplish this," said Olin, coach of the Afton Alps Alpine racing team. "She's a competitor. I'm sure this is super hard for her."

Vonn's post — her only public comment — said she was "devastated" to miss the Olympics. Publicist Lewis Kay said she will have another surgery soon on the anterior cruciate ligament that originally was torn in a crash at last February's world championships, then reinjured in November. Her hope is to be healthy for the 2014-15 World Cup season and the 2015 world championships in her current hometown of Vail, Colo.

Her absence from the Olympics could be painful for others as well. Vonn, 29, is the most successful female ski racer in American history, and the U.S. women have underperformed without her this season. NBC — which paid $775 million for the rights to broadcast the Sochi Games — will miss her high-wattage star power. Olympic sponsor Procter & Gamble had built an advertising campaign around Vonn and her mother, Lindy (Krohn) Lund.

Orthopedic surgeon Dr. Scott Rodeo, who has not treated Vonn but has served as a U.S. team physician at three Olympics, said that repeat knee surgeries are less predictable. But he added that elite athletes such as Vonn can return to their previous form.

Olin is betting on that. After coaching Vonn for five years in her youth, he knows how driven she is, and he expects to see her ski fast again.

Burnsville native Lindsey Vonn announced she is not going to race in the Sochi Olympics because of a right knee injury that will require additional surgery. The 29-year-old American won two medals at the 2010 Vancouver Olympics, including a gold in the downhill. She is also a four-time overall World Cup champion.

"To cheer her on and see her on TV will definitely be missed," he said. "But she's Lindsey. I have no doubt she'll be back for the world championships."

Vonn tore the ACL and the medial collateral ligament in a frightful crash at the world championships. As she prepared to return to World Cup racing in late November, she crashed in training at Copper Mountain, Colo., and partly tore the reconstructed ACL.

Only two weeks later, Vonn made her season debut with three races in Canada. She decided to scale back her pre-Olympic schedule and did not race again until a Dec. 21 downhill event in Val d'Isere, France. During the race, her knee gave out, and she skied off the course in pain.

Vonn still expected to ski at the Olympics. Tuesday, her publicist issued a statement that said she sprained her MCL in Val d'Isere. "Coupled with the torn ACL," the statement said, "[that] has made it impossible to stabilize her knee and be ready to safely ski again next month."

On Facebook, Vonn wrote that "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."

Rodeo, of New York's Hospital for Special Surgery, is the team physician for the NFL's New York Giants and performed knee surgery on former Yankees outfielder Hideki Matsui. He said it appeared Vonn was "very, very careful'' through her rehabilitation. But even if the knee passes strength and stability tests, he added, a re-tear can occur, because there is no way to know how the repaired joint will stand up to the high stress of ski racing.

While an athlete could resume skiing eight or nine months after surgery, Rodeo said, it takes about a year for a repaired knee to be truly normal.

Vonn won downhill gold and a bronze in super-G at the Vancouver Olympics, and her 59 World Cup victories are the most in American history. The U.S. women's team has struggled in her absence this season. Mikaela Shiffrin, a rising star who won the gold medal in slalom at the 2013 world championships, is ranked fifth in the overall World Cup standings; the next American, Julia Mancuso, is 32nd.

The Olympics provided a major incentive for Vonn during her recovery from last spring's surgery, and she will have similar goals to push her this time. She is only three short of tying the record for most career World Cup victories, and she has said that breaking Annemarie Moser-Proell's mark of 62 would "mean everything" to her. She also has long anticipated the 2015 world championships on her home mountain.

Over the years, Vonn has become well-known for her resilience, which has her — and her supporters — remaining optimistic.

"In looking ahead, I have every ounce of confidence that Lindsey will be in the starting gate next World Cup season, ready to compete," said Bill Marolt, president of the U.S. Ski and Snowboard Association. "She knows the hard work it takes to get to the top and still has significant goals to achieve in what has been an incredible career."