Sounds completely made up. No way a bruise, even a serious one, can keep an olympian out of the olympics....
I think a pretty serious bruise on an area that you put a lot of stress on in your activity could do it, depending on your pain threshold. You really lean on your calves/shins while skiing various events. That probably isn't please with a messed up leg.
I bruised my shin right above my ankle after taking a slap shot off the boot in a game a few weeks ago. I went on a ski trip that weekend and the pain from just the walk from the lodge to the base was enough to sideline me for the bulk of the weekend. Now, I am not an olympic athlete about to miss out on my chance to sweep 5 gold medals so my determination to stay on the slope may have been slightly lower than hers, but good lord, ski boots strapped down on an ankle/shin injury is all kinds of awful.