Let's crunch some numbers shall we?
2008-2009: 20.5 PPG, .457 FG, .391 3PT, 5.6 RPG, 3.6 APG
2009-2010: 18.3 PPG, .472 FG, .414 3PT, 4.4 RPG, 3.1 APG
2010-2011: 18.9 PPG, .497 FG, .374 3PT, 5.4 RPG, 3.3 APG
2011-2012 (so far): 17.4 PPG, .415 FG, .362 3PT, 4.9 RPG, 5.4 APG
Yeah, numbers are down across the board but is the question is, is this an aberration or is he just not well adjusted for the shorter season? Is he injured but not telling anyone about it? The FG percentage is a drastic drop so this is an indicator he's got stuff going on that we don't necessarily know about.