I am not a Doctor
But what I do have is first hand experience. I think he probably rolled his ankle. In doing so, some times it sprains the ligament or tendon, but if you do it just right the tendon which I am told is the strongest in the ankle will actually tear the bone apart rather that separating from it. Now the treatment and prognosis. He will have a choice of a boot or a cast. No wieght bearing, so he has an opportunity to build or maintian upper body strength with crutches. He will have the cast or booth for 6 weeks to 2 months. When he comes out of the boot, I know he is an athlete, but I would think two to four weeks of physical therapy. He will heal just fine, and I would imagine will be able to take part in voluntary drills during the summer. He will need to walk and run on it to build the ankle. And one additional thing. He will have the ability to predict rain showers.
That being said, maybe Doc can give us the diffinitive outlook. After all he is a Doctor.