Matt Holliday's Diminishing HR Power

Back in April I predicted that:

I expect Matt Holliday to be a bust in the American League. I wish there was some place that would take a prop bet that at least one Rockies outfielder will have as many or more HR than Holliday this season.

I was right in my prediction so far (Brad Hawpe has 13 HR to Holliday's 8) but I didn't spot the trend. Now the trend is painfully obvious.

In 2007 Holliday hit a HR on average every 17.67 at bats. In 2008 it was a HR every 21.56 AB. This season it just one HR every 37.75 AB. If the progression continues then in 2010 we can expect to see Matt Holliday with Coco Crisp-like power numbers. I'm not even sure that even a return to the NL at this point will stem the tide for Holliday. We may have already seen his peak years.