However, if anyone is injury-prone, it's probably Smart due to his style. I mean, the very thing that you love about him (his hustle, determination, and physical nature) also has its risks.
I think this is an important point.
Obviously we all love to see Celtics players giving full energy and effort out there. It's great to see that Smart is willing to sacrifice himself to make plays that help the team win.
At the same time, the NBA season is long. Winning a title requires winning 4 straight playoff series. That means contributing in a big way, on a night-in, night-out basis -- which is what you want from a star player, i.e. what we have all hoped Smart can be -- has to occur over the long haul, every season.
It's really hard to do that and stay healthy if your primary way of contributing is by throwing yourself around the court and sacrificing your body to make players. In other words, being a star means you have to know how to produce without going balls to the wall all the time. That is, unless you're a freak of nature like Russell Westbrook.
This is part of why Manu Ginobili has always been best coming off the bench, by the way. His thing has always been premised on going all-out, never holding back. The Spurs knew from early on that he couldn't do that 30+ minutes a night and avoid major injury.