Bosoxmal, I sure hope he isn't. Important, no question. But we got got killed by the Guardians last year because of three lousy starters, not one. They were ones with the deep rotation, remember? This year they are just as deep and can probably withstand an early win by Sale. What's more, they have hit Sale awfully well this year and before this year.
Our 2013 WS win was mostly about our great pitching, but even then Lackey was as important as Lester. Lackey was the guy who held the Tigers scoreless against the Tigers and Verlander, who gave up just 1 run. Plus the bullpen was fantastic. Don't forget that in 2013 we still had Papi in his prime which meant good hitting and leading the AL in runs scored. In the postseason we got some very timely hitting, some clutch hitting, but not a whole lot of hitting.
Sale can't fix our hitting, and he can't be the totality of our rotation. In fact, it may be in his case that less is more, that Farrell should not want to make him the iron man.