The Spurs should not sign Drew "Black Hole" Gooden. He played reasonably well last season---moments of awesomeness and moments of disappearing or turning the ball over---but he doesn't fit into the Spurs' plans, I think.
Bowen will return and be the backup SF. A wing rotation of Manu, Bowen, Mason, and RJ is juicy.
As people have noted, the Spurs need to address the PF/C situation. Mahinmi will get a shot. McDyess and Sheed are on the radar, I'm sure. The Spurs are probably considering trading some combination of Bonner, Finley, JV, and Mason. Splitter will be with Tau.
The Clippers need to get rid of one of their bigs.
Trade for Collison.
If that doesn't work . . . sign Rasho, maybe?