The New Orleans Pelicans were a disaster on defense in the first couple weeks. Not only were they the worst defense in the league but opponents were still getting to the rim at will in addition to shooting a scorching hot percentage behind the arc. There isn't much going right on defense when opponents are scoring over 1.1 points per possession.
As I stated two weeks ago Darren Erman has fixed a poor defense before and helped turn the Boston Celtics into an excellent defense in the span of a couple weeks.