I'm sure someone else already said this, but it's a win-win for the Sox and Sale. Sale guarantees himself a payday and at worst he will be underpaid for a few seasons, no big deal.
As far as the Sox are concerned, best case they lock up a premier starter for cheap. Worst case they aren't on the tab for too much per year if Sale's health goes south.
"We drink because it's good, because it feels better than unbuttoning your collar, because we deserve it. We drink, because it's what men do." - Roger Sterling