After the initial stages of rehabilitation
After the initial stages of rehabilitation and rest you will get back on your feet.
So thinking back at the first paragraph the function, loading and anatomy of the tendon.
When you are rehabilitating it, a lot of people try to run before they can walk. For example when you are running you are springing off one foot onto the other, therefore you need that propulsive force to be coming though one foot.
That means all your body weight, gravity and extra forces are going through one leg. If that tendon is not properly rehabilitated before all this force is going through it, you will cause a re-injury.
Therefore the end stage of rehabilitation is EXTREMELY important to get you back to pre-injury