I think 5 years seems like a bit much, but man, it's not terrible considering the market. Fucking Greinke got 6/147. Sanchez got about half that.
Stats over last 3 years:
Sanchez: 587 IP, 526 K, 182 BB, 50 HR, 109 ERA+, 12.0 fWAR, 9.0 rWAR
Greinke: 604 IP, 582 K, 154 BB, 55 HR, 106 ERA+, 14.1 fWAR, 7.9 rWAR
And they are basically the same age.