Dead money happens. Sometimes it is unavoidable, such as when it is due to career-ending injuries, which are usually not foreseeable. More often teams take dead money charges because of declining skill or because the team needs to make room for a more important player.
Dead money is defined as money a team paid to a player who at the end of the season was not on a team’s active or inactive list. Fans usually think of dead money solely as signing bonuses already paid to a player but which have not yet been accounted for on the cap for a player no longer on the team.