Did Dallas acquire his Bird Rights (if there were any) when they traded Harris for him?
If so, I don't see how Cuban lets him walk; he'll probably match or beat any other offer out there, which likely won't top the MLE.
In other words, I think Kidd can expect $5 mil next season, and perhaps a little more.
The Mavs can just barely get below the cap far enough to offer a max contract or close to it in 2010. Signing Kidd to a $5mil or more contract, takes that option off the table, and it's Dallas' best remaining opportunity to build a legit contender with Dirk on the squad.
They have Kidd's bird rights but it's not an easy decision for Dallas. That said, I expect them to sign Kidd, and use their expiring contracts in a bunch trades. That plan probably won't work .... but it'll be fun to watch Cuban try though!
I think three teams, plus Dallas, that need to look at Kidd strongly are --
Houston, Lakers and Portland -- The Blazers have the cap space to make Kidd an offer over the MLE ... otherwise I think Kidd is looking at the MLE.