"In such a deal, Brunell, 36, likely would end up with a considerably lower cap figure, with a portion of his salary converted into a bonus, and a base salary closer to $1 million. Although he would make much less than $5.2 million, he would have job security for next season and some guaranteed money from the new bonus. Base salaries are not guaranteed in the NFL, and each team must fit under the $109 million salary cap."
washingtonpost.com