Certainly, and something like an Achilles injury is usually much more of a freak accident. Seen it a few times and it's someone running on a treadmill or a fastbreak in basketball with no one around them. Those are the scary injuries, similar to Webber blowing out his knee but also are often a result of balance issues and over compensation. An example is that when your body is feeling pretty good and you receive contact, the natural chain reaction is for your core to immediately tighten which offers support/balance through out the body and softens the blow. When you're not feeling that good your core might not fire correctly, resulting is a greater deal of pressure on a knee or ankle or shoulder which can be the difference between a sprain and a tear.
Still, a great deal of injuries happen when someone isn't mentally sharp and 100% there and fatigue is many times a cause of that. At the same time there isn't a whole lot you can do with pro athletes. They're not weekend warriors.