Here are a couple of references:

"Salaries are broken into two categories. The base salary is just that, a base salary that counts toward the salary cap. The second includes all signing and guaranteed bonuses divided over the term of the contract. The second salary does not include performance bonuses"

- http://findarticles.com/p/articles/m.../ai_n19062003/

"From information gathered in the Players Union release, the Fire's current salary amount against the cap is $2,496,210.00. This number is reached by simply adding the base salaries of each rostered player. The Fire's total "guaranteed compensation" for 2010 is $2,890,293.00 although the base salary number is the figure used when determining the total cap dollars used."

http://www.chicagonow.com/blogs/chic...#ixzz1BENHkVC0