Great question. Exactly the right one.
Faith and trust are not words I use when discussing baseball. I just look at the numbers and in this case they scare me. Before the DL stay of 2 weeks, Sale was just about a shoo-in for Cy Young. Since he came back, he has struggled and for sure hasn't gone beyond 5 innings. Last two times out, he got scored on. The Yankees love to hit against lefties, especially lefties who might not have their best stuff. Remember last October when Sale also did not have his best stuff?
I am not saying Sale can't do the job on Friday, but me, I'd like a little insurance because of the past month and a half and especially his last outing when the gave up 3 and could not throw more than 92 mph and sometimes threw 88 or 89 mph.
Still, you have used the operative word--faith (or trust will do)--because I suspect that our rookie manager will decide as you have that faith or trust are far more important than niggling statistics and a small sampling at that.
Oh, as moonslav pointed out, walks are probably not an issue with Sale. But giving up runs appears to be. To me, anyway.