Because the Celts have their system firmly in place, and they have players available at the positions played by ETM and JJJ, there is no reason to play either of them much this season. Garbage minutes is all they deserve at this point. Neither has had a full training camp or a dozen practices, and neither has the experience and know-how of Daniels, Dooling or Bass, or even Wilcox and Stiemsma (who is 26 yo). Bradley cut his teeth in practice and the D-League last year, and these two will have to do the same.
Now, if JJJ was 6'11" and weighed 260lbs, I'd push for him to play, but he isn't, and Stiemsma is, which is a big reason why he's getting playing time.
The best future for these two is cutting their teeth this year, listening to the vets, packing on some muscle, and coming back next year for a full training camp. There will inevitably be big turnover on next year's squad, and each of these guys will probably have a better shot at playing time.
Comparing them to other rookies on crappy teams is ill-conceived. Marshon Brooks is taking the second-most shots on a team with the second-worst offense in the league. With Deron Williams out, he's the Nets only capable offensive player who can create his own shot; the Nets' offensive system is terrible and they don't have the right players to put together a functional system. On the Celtics, he'd be in exactly the same bench spot as ETM.
As long as ETM and JJJ keep their spirits up and continue working hard, there is no reason to doubt either of them. At best, they'll both become key contributors down the line. At worst, they'll up their trade value.
