I do think as well that the surgergy probably does have some effect and but I still think he's learning the NBA game. Like you said -LX- there seems to be a correlation between when he plays well on offense his defense usually suffers and when he plays poorly on offense he plays well on defense.
Again, not to bring up comparisons to Dirk, but Dirk almost went through the same thing. I will say though, that I still think we're using Bargs
incorrectly at points. I just think he's one of those guys who need a "free reign" to create, almost like a PG and not given a job to do like one has to do in the low post.