Hutchison threw 185 innings in his first full season back from Tommy John Surgery (most teams cap innings at 140-150 in those instances). Verducci seems to think Stroman and Norris are injury risks due to having an excessive increased workload from the year before, and while stuff like that needs to be taken on a case by case basis, it's still worth keeping an eye on. Maybe those guys keep pitching well, and I hope they do, but you can't bank on it. Adding a Shields type or hell just adding depth in general would have been nice for the event that you do have to deal with injuries. Last season was abnormally healthy for the Jays staff. With DIckey and Buehrle that can be expected, but the more youth you count on, the more risk is involved.
That's why, despite my feelings on Sanchez (he's not a starter long-term, IMO), I think the Jays should put him and Norris in AAA, Estrada as the #5, and Redmond as the long man. That way you have both Norris and Sanchez stretched out in case of need, and then the team is 7-deep with some intriguing arms in Double-A that might get promoted quickly (Boyd, Cole, etc).