Two and a half years ago, gymnast Shawn Johnson went on a ski trip to Beaver Creek, Colo. On the very last run of the day, everybody else in her group went down an expert run. Shawn, who by then had become a pretty good skier herself, opted to go down a super-easy trail.
Everyone else made it down safely.
About halfway down her run, though, Shawn lost control. The safety release on her ski didn't work; her ski caught in the snow; and she rolled over on her left knee. At that instant her knee popped.
That pop led directly to the announcement Sunday that pretty much everyone in American gymnastics knew was coming, had even already accepted but had nonetheless been dreading: Shawn Johnson, 20-years-old, was retiring.
She said on a conference call with reporters: "Time ran out. I had to accept the fact it wasn't a possibility anymore."
The timing here is everything. The U.S. nationals get underway this week. Shawn wanted this announcement out there so that the spotlight would, appropriately enough, be on those competing, not on her.
She'd had a conversation Friday with her longtime coach, Liang Chow; there had been ongoing conversations with Martha Karolyi, the U.S. team national coordinator. Everyone was assessing the upsides and, at the same time, the hard truths:
Johnson was an able, gutsy competitor. She won four medals in Beijing -- three silver, one gold. She was the 2007 world all-around champion. As Steve Penny, the president of USA Gymnastics, would put it on the call Sunday, Shawn "always delivered ... she was always going to be there with tons of guts and ready to go."
After taking two years off from gymnastics, after winning "Dancing With the Stars," after the ski wipe-out, she came back to the sport and made the Pan Am team last fall with her eye on London.
But the knee just would not cooperate.
It was a "constant fight" all along with the knee, she said, adding at another point in the call, "Talking to Chow and talking to Martha and coming to reality, I couldn't push myself any further."
Asked about making the 2012 team, she said: "It would have taken everything I had, and it would have taken luck."
What's next remains immediately unclear. Shawn is dead-set on going to college. Moreover, she doubtlessly will continue to have sponsor opportunities because her agent, Sheryl Shade, has done a terrific job behind the scenes over the years and she is, as Penny said, the embodiment of the "girl next door."
In the near future, Shawn predicted that the U.S. women's team -- whoever is ultimately on it -- will be the one to beat in London. She said she intends to be their "biggest cheerleader."
Who knows why somebody with unbelievable balance fell down and popped her knee on a ski run she surely should have had no trouble handling? Life works in mysterious ways.
To Shawn Johnson's credit, she has always been extraordinarily gracious in dealing not just with the injury but the aftermath and the inquiries about it. Of which there was, naturally, one more on Sunday.
No surprise, she was a class act: "Everything happens for a reason. I can't take it back. I can't regret it."
Alan Abrahamson is a freelance contributor for TeamUSA.org. This story was not subject to the approval of the United States Olympic Committee or any National Governing Bodies.