Ok the guy has been up and down and pretty ugly on the surface. The injury he incurred this season has had to have had a marked impact on his performance. The most glaring stat that sticks out to me is his GB%, and more specifically how this year's number compares to his previous three years.
Year GB% LD%
2004 62.6 14.1
2005 63.3 18.0
2006 60.8 17.3
2007 51.9 21.5
Thats a significant difference. To illustrate the importance of this further here is the likelyhood of getting a hit off of a GB and a LD using 2006 league averages.
Type % of BIP H% on BIP H% as BABIP
Line Drive 15.89% 74.77% 0.748
Ground Ball 41.24% 23.62% 0.236
Now look at his BB/9 over the past four years:
Thats a pretty crazy jump, right?. Based on regression toward career mean, we should expect him to regain some of his control (barring any problems associated with physical injury) and lower that number. The same can go for his GB%. The differences vs. career numbers are just too staggaring. He's posted above or close 100 ERA+ numbers for the past two years. He should improve his performance (barring any injury related problems) closer to his career numbers through the rest of the season.