I think that's an unfair label. He broke his foot which can happen to anyone and then there's some mysterious injury/illness/whatever that cost him a month this season. But injury prone is usually reserved for that kind of guy who keeps getting nagging injuries and historically that has not been the case for TJ. Granted, his NBA career so far is a bit worrisome but he played 2 years in college without missing a game and I'm unaware of anything before that either.
I still believe we're going to find a completely different explanation for his recent absence than most people think. I hate to engage in wild speculation and that's all that's available right now but nothing about that went situation felt right. He had been playing great for us and then all of a sudden, he was no longer performing well.
The coach even took him out of a game and benched him for the rest of the contest and afterwards, it was clear Watson was disappointed in/by TJ. Then he sits for another game, maybe two, without explanation, before the news is finally released that he suffered a "minor head injury" and would be out for an undisclosed period of time which turned out to be almost a month.
Now, he's back but he's a shadow of his former self. He'd been playing good defense and very good offense and that just isn't the case anymore. And a 13 game absence doesn't explain this kind of return to work. Something strange happened and something strange is still going on. JMO.