Pau Gasol is shooting inordinately low on short and mid-range jumpers. Shooting percentages at these ranges can have some crazy volatility -- ask Ersan Ilyasova, who shot brilliantly on them last year and is struggling this year.
So Pau's scoring drop -- which has been nearly the complete source of his apparent decline in quality, with the caveat that defense is really difficult to measure on an individual basis -- is based on fewer attempts and stunningly low conversion on short and mid-range jumpers.
That's all of it. Pau Gasol looks like he sucks because he's missing those half hooks, those pop-out jumpers, those extended post turnarounds.