It is a question mark, but he has been playing fine for a while now. It seems to be a bigger problem for athletes when it happens later in a career, when they are less able to heal. Younger athletes seem to be responding much better to microfracture, although it obviously is still something you worry a little about. Don't forget our own Spencer Hawes has already had microfracture surgery himself.
The last part from the quote, Unlike hyaline cartilage, fibrocartilage does not have the same strength and resiliency of cartilage normally found in a joint. Therefore, there is a chance that the cartilage stimulated by a microfracture procedure will not stand up over time.
It's not about how he is doing now, but how will he be doing in 3 years? 5 years? He's 26 now and entering his prime.