Athletes are not perfect and can make poor decisions, like any other mortal human. What is the cause? 

In the data that we gather from our decision-making assessments, we see that stress is often the primary reason for poor decision-making

Athletes normally lead a very ordered and disciplined life - when training or competing. However, indiscipline and a set routine can go out of the window when the athlete gets home after training or competing. More often than not their personal lives or off-field lives are very much more reactive and unstable, compared to when they drive through the gates of the training ground. Analysing and understanding the 'causes' allows one to deal with the 'effects' which in this case seems to be poor decision-making.

It is interesting to note, that despite his injuries, Tiger Wood has not won a 'major' tournament since his marriage fell apart.

More often than not the problem is on the personal side and not when  playing/competing.