So the rotation is currently set with Zambrano, Garza and Dempster (not necessarily in that order) but what about the last two spots. Canidates seem to be, in no particular order, Carlos Silva, Randy Wells, Casey Coleman, Jeff Samardzija, Andrew Cashner, James Russell and Braden Looper.
Lets start with the top. Silva had a pretty good year last year, especially considering his performance in Seattle for the last couple years, and has the most starting experience of the bunch. Next we have Wells who had a pretty impressive rookie year and then a pretty dismal sophomore year, but had horrid run support for most of the year. I am going to jump to Samardzija next.......he showed tons of promise, but for some reason cannot seem to cut it as a starter and maybe at all in the bigs. Like so many players in baseball history he does well in the Minors but can't seem to handle the Majors. Coleman, Cashner and Russell have done well out of the pen but starting is a whole different beast considering hitters get a better look seeing them 3 or more times a game on average. Looper, a non roster invitee, had some knee and payroll problems so who knows how well he can do at this point after taking 2 seasons off from the game.
With all that being said I see Silva and Russel starting the year off in the rotation.