The new collective bargaining agreement that emerged in December 2011 after a 161 day lockout changed a number of rules on how sign and trades work.
Here's a summary of the new rules:
- Sign and trade contracts are reduced to a maximum of 4 years, with 4.5% percent raises. These are the years and raises used for non-bird players. In the past CBA, you could give the player maximum raises for maximum years if you had their bird rights, which would be 7.5% raises over 5 years in the current CBA.
- Teams more than $4 million above the luxury tax cannot receive players in a sign and trade deal. If a team acquires a player in a sign and trade deal, then the team cannot go $4 million or more above the luxury tax for the remainder of the salary cap year. There were previously no restrictions.
- There are also some changes to how Base Year Compensation is applied, but these are not applicable in the Andrew Bynum Situation, so I'll skip those for now.