I don’t think the news today changes anything.
It’s been clear for awhile he has a small meniscus (due to the partial meniscectomy surgical trim resulting in less cushioning in the lateral compartment) and “some” cartilage damage and arthritis in his knee. The data for PRP working is weak/anecdotal at best, but very little risk of harm. No surprise they are trying it.
From the outside, it’s not clear that anything done last season changed the natural history of his disease. He sustained a meniscus tear and had a standard procedure to address the tear, trimming a portion out. Presumably this tear wasn’t amenable to a true repair regardless of when in the season it happened.
Coming back a month later is pretty typical, especially without symptoms at that time. Playing later on the clearly sore knee with recurrent fluid buildup (as reported) is where it gets dicier. Apparently he was told he wouldn’t do any added damage, and this may or may not be true.
It’s entirely possible whatever extra cartilage damage he sustained could have happened whenever he started playing again anyway. Having said that, if you are in pain like that the bone below the cartilage is likely bruised and there’s some data that is going to cause the above cartilage to flake off and be more at risk (a bit of a chicken/egg scenario).
In general, I’m sure he would have been given more rest of it wasn’t the playoffs out of an abundance of caution, like they are doing this season. Without being able to see his MRI, I’d put the error bars on the end of this season/career extremely large. A return to peak performance is certainly possible, don’t give up hope (a large number of pro players I see have “some arthritis”, it’s not automatically a death sentence, the degree and location matters a lot). Going the way of Kemba is also on the table.
Just a long winded way to say, keep your fingers crossed. No one really knows at this point, including his docs most likely.