The best site on the Internet for all questions about the CBS and salary caps is:
http://members.cox.net/lmcoon/salarycap.htm
Here's what it says about buyouts:
59. What is a contract buy-out?
Sometimes players and teams decide to divorce each other. They do this by mutually agreeing that:
•The team will waive the player;
•If the player clears waivers, the compensation protection for lack of skill (see question number 90) will be reduced or eliminated;
•Optionally the payment schedule for the remaining salary may be shortened or lengthened.
For example, the Celtics did this with Dino Radja prior to the 1997-98 season. They mutually agreed to reduce Radja's compensation protection to 50% of its value, and then the Celtics waived him. When he cleared waivers he was paid the 50% he was owed, and he was then free to return to Europe.
But there's a twist, which needed an arbitrator's ruling during the 1999-00 season to resolve. As detailed in question number 90, on January 10 all contracts become guaranteed for the rest of the season. Compensation protection insures the player against loss of salary after being waived for lack of skill. But if he is waived after January 10, then he doesn't lose his salary, so the compensation protection does not kick in. Even though the team & player can mutually agree to reduce or eliminate the player's compensation protection, he is still owed his full salary if waived after January 10.
This was challenged by John Starks during the 1999-00 season. Starks had been traded to the Bulls, and wanted to sever ties with the team after January 10. The arbitrator ruled that in the last season of a player's contract, the team and player could choose to eliminate the contract guarantee that kicked in on January 10. Starks and the Bulls were therefore free to agree to a divorce (with no money owed to Starks) as described above.
There is one other type of buyout described in the CBA. When a contract contains an option year, a buyout amount for the option year can be written into the contract. The buyout amount may be up to 50% of the salary for the option year, and is payable with the exercise of an ETO or the non-exercise of an option.
60. How do buy-outs affect a team's salary cap?
The agreed-upon buy-out amount (see question number 59) is included in the team salary instead of the salary called for in the contract. If the player had more than one season left on his contract, then the buy-out money is distributed among those seasons in proportion to the original salary.
For example, say a player had three seasons remaining on his contract, with salaries of $10 million, $11 million and $12 million. The player and team agree to a buyout of $15 million. The $15 million is therefore charged to the team salary over the three seasons. Since the original contract had $33 million left to be paid, and $10 million is 30.3% of $33 million, 30.3% of the $15 million buyout, or $4.545 million, is included in the team salary in the first season following the buyout. Likewise, 33.33% of $15 million, or $5 million, is included in the team salary in the second season, and 36.36% of $15 million, or $5.455 million, is included in the team salary in the third season.
The distribution of the buy-out money is a matter of individual negotiation. Changing the number of years in which the money is paid does not change the number of years in which the team's team salary is charged. In the above example in which the player's contract is bought out with three seasons remaining, the buyout amount is always charged to the team salary over three seasons. It does not matter if the player is actually paid in a lump sum or over 20 years (a spread provision).