walker and glenn both got a signing bonus, not sure how much. if i remember correctly it was a good portion of their contracts. signing bonus's are paid up front but usually the money is split up evenly and count against the cap yearly for the life of the contract. example 10 dollar signing bonus for 5 years counts 2 dollars per year.
now if that player is not playing up to expectations or even if hes cut that money still counts against you. plus the money it takes to replace that player.