As someone who drafted Aaron Rowand, rather highly I should add, in a few fantasy leagues this season this is a question I've been asking myself quite a bit.
Rowand is on pace for about half as many homeruns in the same number of at bats that he had last year. I could accept the loss of homeruns if some of those balls that were homeruns last year ended up as doubles this year, but that's not the case either. Rowand's double rate is down this season too. So what is causing the drop?
Let's take a look at his career numbers. I've combined his 2001-2003 seasons into one 'full' season.
As you can see, Rowand's 2005 season closely mirrors his 2001-2003 numbers, falling just short in the HR category.
Maybe I'm simplifying the problem a little bit, but when you look at Rowand's GB/FB ratio for those corresponding times it becomes plainly obvious where the power went.
Rowand was laying out ropes all over the field last season, which resulted in his high batting average and tons of doubles. This year, he's hitting the ball just as hard. That's not his problem. He's just hitting the ball on the ground more. Groundballs have a 0% chance of becoming a HR, and a minute chance of becoming a double.
That's as simple as I can make it. Get the ball in the air a little more Aaron. The team will thank you.