If you do the following, you can use current season data (through Aug. 14) to make a rough guess of the top pitchers for next year:
1. Use Component ERA or something similar (takes the raw data of a pitcher and computes what his ERA should be)
2. Adjust this based on the pitcher's home stadium "park factor"
3. Adjust this based on the pitcher's team's park-independent defensive efficiency
4. Make a final adjustment based on the league of the pitcher
Here are the top 10 (all project to be * starters):
1. Dan Haren
2. Tim Lincecum
3. Zack Greinke
4. Josh Johnson
5. Josh Beckett
6. Javier Vazquez
7. Ubaldo Jimenez
8. Jarrod Washburn
9. Roy Halladay
10. Justin Verlander
I estimate that Chris Carpenter as a non*-starter would be very near Halladay/Verlander value, but would be just outside the top 10.
I realize component ERA isn't a perfect formula, but it offers a starting point for tinkering and guessing. You could also use EqERA to make projections.