What will become of that money?
Here’s a major clue:
Marc Stein of ESPN:
The Spurs didn’t have to pay Duncan. Teams aren’t obligated to pay players who stop showing up for work, and Duncan was clearly done working.
But with him waived — assuming he clears waivers — San Antonio is on the hook for the guaranteed portion of his salary. That was the full $6,393,750, though it’s possible the team and Duncan agreed to reduce his protected salary (a buyout). The Spurs can either pay Duncan’s protected salary all this season or stretch the payments and pay a third each of the following three years.
Presumably, this was all pre-arranged. Duncan and the Spurs know potential buyout terms, and they probably agreed to whether or not it will be stretched.
Unless Duncan suffered a career-ending injury, of which there’s no evidence, his salary will continue to count against the cap — assuming there’s remaining salary. It’s possible Duncan agreed to make his contract fully unguaranteed, because the process of waiving him was easier than excluding his salary due to him no longer reporting.
But my strong hunch is the Spurs will pay Duncan, who alleged a financial advisor stole more than $20 million from him. It’ll cut into their cap room, but it’s also a nice parting gift for the franchise icon.