The following chart shows how the pitches of select young MLers compare to each other. I used the enhanced gameday data to come up with this crap. At the least, you can look at the "% thrown" column which tells how often that pitch is used by that pitcher and also the speed of that pitch in the "mph" column then things get a little more difficult to understand. But a relatively small "pfz" value (vertical spin) means the fastball has more of a sinking action. There's more detail here and I also described it in more detail here and if you go to that last link you'll also see a more detailed look at Shields (e.g. what percent of swinging strikes are on changeups for Shields?). Also somebody at the baseballanalysts has written about some of the data as well. So here:

The Peavy data is to be taken with some salt as it was hard to differentiate between his 2 seam fastball, slider, and changeup.

I'll also repeat what I said at the end of the Slowey thread:

Slowey pitch selection: 73 fastballs, 16 sliders, 5 changeups, 5 curveballs

Initial speed of those pitches, respectively according to enhanced gameday:
90.1, 83.2, 78.3, 73.6

And the home run was off a 84.0 mph slider that had the least break of the bunch, but wasn't really an outlier.

He pitches pretty high up in the zone. It looks like  only 2 pitches were below the strike zone, a curve and a fastball.