No doubt he can play, but I can sympathize with the other side of the argument. Looking at the decision now, you have a guy who may not get many minutes behind Mo Williams (who is not old). If you put him on the court with Lillard, then CJ will likely have to be your 2, as he has shown zero ability at this point to run the offense. Sure, he may develop that ability, but Lillard came with it, and look how the Rivers experiment has worked out so far. With Crabbe on the roster, you already have a better defender than CJ and a guy who is legit size.
The somewhat fixed rotation is Lillard starting at PG, spending some time at SG and sitting out the rest. Honestly, I don't see a shortish scoring guard fitting into that role very well. My best hope is CJ is that Vinnie Johnson type of guy who comes in with the second unit and lights it up. But, in 100% 20-20 hindsight I'm not sure he was the best choice given the rest of the moves.