The starting rotation is the complete x factor.
1) Lester 4.82 ERA in 2012, 5.40 in Sept/11. Why, and can he rebound?
2) Buchholz 4.56 ERA in 2012. Only his second full year in the majors. Had a terrible start, nice stretch in mid-season, and a terrible finish. Very hard to predict.
3) Lackey 5.26 ERA as a Red Sox. Coming off missed season and TJ surgery.
4) Dempster career National Leaguer, 5.09 ERA in first and only AL stint last year.
5) Doubront 4.86 ERA in 2012. And jump in innings has him on the 'Verducci list'.
Optimism that several of these guys will have decent seasons is certainly not unwarranted and I hope they do. But there's really nothing there to feel especially confident about.