To those saying RJ wasn't expendable... Kawhi has played better than him for most of the season. It was already well known by Spurs fans that we have our SF of the future a couple games into the season. This kid is long as hell, great defender, and has been showing incredible unexpected offensive stints. What RJ brought to the table is easily replaceable by young players on the team. Not to mention we no longer have him as a defensive liability. Stephen Jackson seems really enthusiastic about coming back, and when he tries he's a huge upgrade over Jefferson defensively and offensively.
Many are saying Jackson is tied down to the shooting guard spot, but he will see alot of SF. I would really love to see Kawhi and Jackson start together. Gives us alot of length on the perimeter which also helps out Blair and Bonner when they are in the game.
The bottom line is from tweets and such S-Jax seems ecstatic, saying he's back "where he's meant to be". This is the best shot he's had since leaving the Spurs really.
As for big men, the Spurs will pursue Diaw and Kaman pending buyouts. But for those saying Tiago+Duncan isn't enough, we just came off a big win last night against the league's best big man. These two can anchor the defense when in the game by themselves. Imagine when they actually start playing together.