This is just my personal feeling/speculation(s), but I have a feeling (not quite 50-50% but close to it) that the power rankings would look something like:
1. SRF - highest upside of the bunch and showed some promise last season in a small sample despite exhibiting a lot of warts such as control issues and the like. Pure stuff is that of a #2, though I just can't see that happening. Let's hope he can improve his command and he turns into a #3, but you'd have to assume he could be effective in other, shorter-burst roles if he can't stop throwing (ten straight) balls.
2. Paulino - has the stuff to start if he can stay healthy and off the drugs (mmmkay?). "realistic" upside is #3 SP, or possible dominant late-inning arm.
3. Borucki - probably a #4/5 type SP, but hard to see his floor being much lower than that.
4. Merryweather - he's tough to nail down due to the TJ, but was throwing hard and seems to have good control of his deep arsenal of pitches. possible range of outcomes are #3 SP to what Thornton is below.
5. Thornton - could be a solid back-end starter, or long-man out of bullpen, or used as an effective post-opener.
6. Perez - probably an RP due to control issues, but upside is immense if he were to ever harness his stuff (but he probably doesn't and could end up a late-inning arm instead).
7. Waguespack - probably an RP, but might be a serviceable depth starter.
8. Pannone - probably an RP, as we saw he was more effective in that role last year.
9. Copping - strictly an RP.