Per ESPN's Marc Stein:
Stunning. The Mavericks at least don't have Kidd on the cap for three more years but the Mavericks present future is undoubtedly in shambles. Kidd has his warts and his play was decreasing by the year, but he was a good fit with Dirk Nowitzki, who is now looking at a sure lottery-bound roster.
In turn, I speculate Dallas will now throw that 3-year, $9 million offer (or something very similar) to Delonte West. There are rumors of Aaron Brooks and Ramond Sessions, but West provides a much better duel threat point guard option and he already knows the system.
Unfortunately, West won't be a complete quick fix. The Mavericks had a formidable offense when Kidd and Dirk were on the court. Now the Mavericks will have to scramble to make sure West stays and in turn be ready to hand more minutes to Rodrigue Beaubois, Dominique Jones and Jared Cunningham.
If Dallas brings back West and no other changes are made, the Mavericks are looking at a starting lineup of West, Beaubois, Marion, Dirk and Haywood. Unfortunately, West and Beaubois rarely played in the backcourt together last year, and there isn't much data on how such a tandem would perform. (Here is the Beaubois-West lineup that got the most minutes, for reference.) One would think West would act much like a Jason Kidd-light, with West initiating the sets and Beaubois working off-ball and free to score and penetrate and create. Not to mention the clear defensive upgrade Beaubois and West playing more minutes would bring Dallas.
It's an intriguing tandem, but unfortunately an inexperienced one. When West ran point guard duties last year, the Mavericks ran into trouble getting Dirk the ball in the right spots. This is also banking on Beaubois making "the next step," whatever that ambiguous statement really means (Beaubois finding his shooting form from his rookie season would be a nice start.)
In the end, it's nice to know that the Mavericks won't have to employ a starting point guard that is 41-years-old but it comes with a risk -- the unknown. A Kidd-Nowitzki led offense wasn't without its faults, but it was also a stable offense, a reliable one. There's room for the Mavericks offense to grow into something potentially more without Kidd, but getting there might mean Mavericks basketball isn't as fun to watch as it's been for the last 12 years.