All these are milestones that are reachable in my opinion:
Alfonso Soriano: 66 at-bats from 5,000-30 home runs from 300-109 hits away from 1500.
Reed Johnson: 86 at-bats away from 2500-7 total bases from 1000.
Kosuke Fukudome: None that are reachable, probably because he just started in US a year ago.
Joey Gathright: 92 games away from 500.
Milton Bradley: 133 at-bats away from 3000-101 RBI's away from 500- 190 total bases from 1500-197 hits from 1000 (if stays healthy, he can get it).
Micah Hoffpauir: Hasn't been in the majors long enough to have a chance at any milestone.
Derek Lee: Has not milestones that are reachable this year.
Mike Fontenot: 21 at-bats from 500.
Aaron Miles: No milestone is reachable this year.
Ryan Theriot: 141 games from 500-236 at-bats from 1500-133 hits from 500-33 total bases from 500.
Aramis Ramirez: 43 at-bats from 5000-94 hits from 5000-22 total bases from 2500.
Geovany Soto: 4 RBI's from 100.
Koyie Hill: 4 games from 100.
Paul Bako: 18 hits from 500.
Carlos Zambrano: 4 wins from 100-118 innings from 1500.
Ryan Dempster: 75 innings from 1500.
Ted Lilly: 9 wins from 100-143 innings from 1500.
Rich Harden: No milestone he can reach this year.
Sean Marshall: No milestone he can reach this year.
Aaron Heilman: 50 innings from 500- 105 strikeouts from 500.
Kevin Gregg: No milestone he can reach this year.
Carlos Marmol: No milestone he can reach this year.
Jeff Samardzija: No milestone he can reach this year.
Neil Cotts: No milestone he can reach this year.
Chad Gaudin: 51 innings from 500.
Angel Guzman: 4 innings from 100.
Luis Vizcaino: 20 strikeouts from 500.
Kevin Hart: No milestone he can reach this year.
These are all players that are on the team or who might make the team.