True. That tells you more about your team than about me though.
Well, it also says that you didn't read up on the subject before posting.
When Cassel voided his contract, it was widely reported as a move to force the Vikings to either commit to him as the starter (and with a new contract) or to allow him to find a starting role with another team. It was never reported as Cassel wanting to leave, just strategically working the options available to him.
The Vikings are semi-screwed because they didn't play bad enough to get a top-5 pick, and there are too many QB-needy teams ahead of them in the draft. Ponder was originally called "the most NFL ready QB" in that draft, and while that obviously wasn't true, the Vikings still reached to pick him #12 instead of the second round. Their GM, Rick Spielman, seems hesitant to make the same mistake twice and has hinted that they very well may wait until the second, third, fourth round to draft a QB. Why reach again?
That combined with a desire to nurture along whomever they draft, is the main reason for re-signing Cassel. Cassel gets to finally be the true starter, the Vikings get a decent veteran QB that they know can win games for them, and their drafted-QB-to-be will get time to learn before being thrown into the fire.