According to new data compiled by Ian Levy and Darryl Blackport of Nylon Calculus (via), the Chicago Bulls led the entire NBA in drives allowed to the basket this season with an average of 28.8 per game.
At a glance, this is not such a big deal, as playoff teams including the Golden State Warriors fell less than one drive allowed per game short from meeting the same average. The Bulls' points per drive and assists per drive surrendered also ranked right around the association's average, so it would initially seem that the volume of looks didn't affect the Bulls perhaps as badly as it should have.
However, because the Bulls gave up so many easy drives to the basket this season, their points off of drives per game tally still managed to rank third worst in the NBA behind only the Pistons and Pelicans. This number also doesn't account for the points generated off of assists that the Bulls' defense surrendered when failing to guard such drives. The X/Y chart below gives an idea of how the Bulls' performance in this area compares to the rest of their basketball peers:
This would all seem to further confirm that the perimeter defense, particularly that of Derrick Rose, was lacking this season compared to years in the past under Thibodeau. It would be nice to have data on defensive drives available from before this season so this theory could be tested, but the data present nevertheless points to the conclusion that the gritty defense once inherent in the Bulls' roster has evaporated entirely. We are well into the age of Fred, so get comfortable.