Pass on Bol...foot problem already
Bol's (7'2'') injury is a navicular fracture. That spelled the end to Ming's (7'6'') career, but it was also the same fracture Joel Embiid (7'2'') suffered and he is doing well.
A lot of navicular fractures are the result of weak foot muscles and plopping when you run instead of running with strength. The the muscles don't absorb the impact, and therefore the bones in the ankle start taking the impact.
One of the biggest problems with navicular fractures is blood flow to the area, leading to weak ankle bones and long healing times on breaks. This is one of the reasons why broken navicular bones can be indicative of bigger issues with big guys.
I'm not a doctor, but I suffered a navicular fracture several years ago. It was misdiagnosed initially, leading to 2-3 months of "rest" hoping for a recovery. When I finally got an MRI, they discovered the navicular fracture and I had to wear a walking boot for 4-5 months (can't remember the duration exactly). I still dealt with pain and weakness in the ankle as I rehabbed for the next 6-8 months, getting slowly better over time. That means it took me a full year before I felt mostly back to normal.
I'm not a great athlete, but I do try to stay active. I'm an average 6'1'' and 190 pounds. Therefore, the comparisons between me and Bol are obviously apples to oranges. Still, the break may or may not indicate long-term concerns.