Sanchez only has 34 AAA innings, and 100.1 innings in AA/AAA. His peripherals were terrible at those levels too. I think it's pretty dumb to just give him a spot on the team because he throws hard and his ERA was shiny in the bullpen last summer.
Also, if they keep him down in Buffalo for a couple of months they effectively get another year of control out of him, I think (because his service time will be less than 3.000 years after 2017).