According to this, you can forget about the Spurs using the amnesty on Jefferson:
http://eye-on-basketball.blogs.cbssp...48484/33013382
[I]
Amnesty clause: As Ken Berger of CBSSports.com has reported,
a new amnesty clause will be in the new CBA, allowing teams to waive one player at anytime during the life of the new CBA. You still have to pay the players but his salary won't count against the cap and luxury tax.[B] But here's a catch: It can't be used on anyone signed
before July 1, 2011. So all that talk about who you'd amnesty would change quite a bit because those players aren't eligible.