So yes, it would seem that the Los Angeles Clippers have signed , or are on the verge of signing, Stephen Jackson. Jackson is a 13 year NBA veteran, 35 years old, and last played in the NBA for the San Antonio Spurs. He was waived by the Spurs just prior to the start of the playoffs last year, despite the fact that he'd been 20 minutes per game part of the rotation most of the season. That little tidbit tells you a lot -- Jackson can play, but there's a cost involved that not every team or coach is willing to pay.
Let's start with some simple bookkeeping issues on the signing. If Sam Amick of USA Today is correct (and he usually is) and the signing is non-guaranteed, then this signing does not significantly limit the Clippers other options for improving the roster. Obviously the Clippers biggest long term need is to improve the front court, where the trio of Antawn Jamison, Ryan Hollins and Byron Mullens have never screamed "contender quality" as bigs off the bench. But when Reggie Bullock sprained his ankle in Cleveland, the Clippers suddenly had a significant short term need. Bullock will be out for a bit, joining Matt Barnes and J.J. Redick as injured Clipper wings. Jackson steps in to fill that void, and will have about a couple of weeks in the rotation, and a month overall, to try to earn a spot on the roster for the season.
There's a common misconception (and I must admit to falling into it a bit myself from time to time) that teams need to wait until January 10, when ten day contracts become an option, before they can experiment with cheap alternatives on their team. That's a classic case of mis-association -- the significance of January 10 isn't that ten day contracts become available -- it's that unguaranteed contracts are no longer available. Ten day contracts are only necessary as an alternative to guaranteed contracts after January 10th.
Now, for a veteran like Stephen Jackson (or Lamar Odom for that matter) there's an open question as to whether they would be willing to accept an unguaranteed contract -- but apparently in this case Jax is willing, given that teams have not exactly been breaking his door down to sign him.
The Clippers are limited in what they can do to improve their roster between now and the playoffs in many ways, the two most significant being roster spots and money. For the time being, Jackson takes the 15th and final roster spot available, but additional roster spots can always be created by waiving a player. Given that Jackson will be the only non-guaranteed contract on the team until January 10, the simplest scenario if the Clippers wish to sign someone like Odom would be that they would waive Jackson to create room on the roster, at some point after Jackson has filled the temporary need on the wing.
The Clippers could waive another player as well, the most likely being point guard Maalik Wayns who has yet to play this season. But it's my understanding that Wayns contract became guaranteed on December 1, so to waive Wayns (or anyone else beyond Jackson) would involve eating salary, and with the hard cap looming about $2.4M away, the Clippers can ill afford to do that.
The fact that the team is in Philadelphia right now provides the perfect frame for the other alternative -- to pay a team under the cap to take dead weight off their hands. The Sixers aren't just below the cap, they're actually below the NBA minimum -- and they'll be looking to take on as many contracts as they can.
With the Clippers over the luxury tax, there are obvious win-win trades possible here. The Clippers could send Wayns to the Sixers, include a million dollars cash which more than covers Wayns' salary AND saves the Clippers money compared to his salary plus the tax on his salary, and both teams would come out ahead. But Philadelphia probably won't do that deal, because their cap space will be in demand, and other teams will probably be willing to include assets like second round picks, not just cash. There's an opportunity cost -- the Sixers can't do unlimited deals, because eventually they'll hit the salary cap (although they could sign and waive about a dozen min guys before they hit it) and they'll want to hoard their space looking for the best deals. The bottom line is that the Clippers will probably be able to rid themselves of either Wayns or Willie Green at some point -- but it's going to cost them at least some money, and probably an asset as well.
So moving forward, signing Jackson doesn't change much. If he doesn't work out, they waive him and are right back where they started (minus a minor cap hit for whatever they pay him in the meantime). If he plays great, they can keep him and figure out a way to get rid of Wayns or Green or both.
As for adding Jackson to this team, we'll see. Chris Paul is a respected and dynamic on court leader, and Doc Rivers is a tough and respected player's coach. Jackson has a lot at stake if he wants another shot at NBA success, so he'll probably be on his best behavior. Will that be good enough? Can he still play? We'll see. He's a career .415 shooter who shot well under 40 percent for the Spurs last season, so he doesn't help the Clippers current shooting woes. On the other hand, with Barnes currently out, he immediately becomes the team's best perimeter defender and resident bad ass.