Last time Rich Harden threw a slider was in 2007. Or, at least in a PITCHf/x game. It is pretty well known, in 2008, that he's left sliders and splitters behind, and throws a fastball and a change-up. The change-up is extra tough, since he can throw it a few ways with a single grip (circle). With no distinguishable difference from his fastball's arm speed, and his ability to dial the fastball up-and-down the speedometer, he can be nearly impossible to hit. He's around the plate, so it does happen (more than his share of home runs), but not often.
The following numbers are for all of Rich Harden's games that are available with PITCHf/x data. They do not include his August 24 start. Tables are sortable, images can be clicked to enlarge.
The most important image in the next series is probably the last, or the last two.
The flight paths paint a scary picture for hitters.
Here are Harden's Out of Zone/In Strike Zone numbers.
Breaking that down by month, starting with May 2008.
Now by pitch
And, starting in May, by pitch by month
That's a lot of numbers. He looks consistent with the fastball, especially when you consider the small-ish sample size for August. The change-up seems to be getting less misses out of the zone, but, you're dealing with small numbers at that point, as seen in this next table.
The Cubs acquired Harden in early July, so, if you squint and think of the May/June as AL and July/August as NL, you could make the claim that NL hitters chase change-ups less than AL hitters. Not saying that I'm making that claim, but you can.