It's not so much that he's bad, he isn't that bad, but next to Dame, who hasn't shown great defense, and likely matched up with either quicker or bigger 2s I'm not optimistic. CJ is only 0.5" taller than Dame and has a 2" shorter wingspan. I know he wants to put effort into defense, and does talk about it (as does Dame), but I haven't seen it yet. I don't think it is too much of a stretch to imagine Hendo, Harkless and Crabbe being better defenders than CJ. It doesn't mean he's terrible, jut not the best, or the most committed.