Derrick Mason ended up costing the Jets under $1 million. That is really nothing in the NFL these days. The salary cap is around $120 million. What the Jets paid amounts roughly in NFL terms to a dinner out for a family.
In exchange for that, the Jets could receive a Draft pick. It will not be a high pick at all. It is a conditional seventh rounder. We hear a lot about early busts and late round hits, but generally speaking, teams tend to get the Draft right. Few gems are available in late rounds relative to the amount of duds. They exist, though. An extra late round pick is like an extra lottery ticket. You would rather have it than not. If a proven impact guy like Braylon Edwards or Santonio Holmes is available in exchange for that pick, you jump on it. If it is a guy like Derrick Mason for whom a better replacement might be in house, getting that pick might be worth it. The Jets might also be able to use the pick as ammo to move up and get a player they want.
The Derrick Mason signing potentially amounts to something in exchange for nothing.