The defense is a unit with many parts which all have an effect on one another. It is true that a corner can only cover a receiver so long, but it is also true that the opposition's tackles can probably only cover Will Smith and dare I say Charles Grant for so long. If a QB sees Jason David playing 10 yards off, it's not going to be hard to complete passes, just as with our awful safeties in coverage a stop and go route is going to work a lot. If Samuel and hopefully McKenzie are our corners and can be in position for 5 seconds then it's going to give Will Smith and Grant and the defensive tackles more time to get to the quarterback. I agree that if true no-one can complain about this signing. I think in our scheme Jason David can also be an asset, rather than a liability playing nickle