There are two very different things going on with the hip. The first is the chronic condition known as femoral acetabular impingement or FAI. This is the core issue with IT. It relates to the shape of his hip ball or cam. This cannot heal but can be repaired with pretty serious surgery as I understand it.
The other issue is a tear (as is being reported) to his hip labral cartridge (labrum). If this is as reported, it can be treated in a number of ways including surgery but this is much less intrusive surgery than surgery to repair the core condition FAI. FAI and the wear and tear of an NBA season likely led to the Labral tear so these are related but very different. (I think this was originally reported as Labral inflammation, not a tear so this seems to be the new news).
So when it is being thrown out that "IT needs surgery", it has to be more specific as to which surgery. I am not a doctor, I just have been doing some surfing to understand this better but I don't think surgery to repair the Labral is all that serious and would not threaten the whole season. The FAI surgery on the other hand is serious but IT has played his entire career (his whole life for that matter) with the condition.
Here is a summary of treatment options for torn Labral from Mayo Clinic:
Treatment choices will depend on the severity of your symptoms. Some people recover with conservative treatments in a few weeks, while others may require arthroscopic surgery to repair or remove the torn portion of the labrum.