Tuesday at 12:01 a.m. Pacific, Hulu pulled all of its video from TV.com, the recently relaunched CBS Interactive site.  A CBS Interactive spokeswoman told us this morning that no reason was given. Hulu’s terse statement suggests that both parties are aware of the rationale and that’s about all:

“Hulu has contractual rights with regards to our relationship with tv.com and we are exercising those rights. Out of respect for their confidentiality, we will not disclose our discussions.”

Instead, Hulu apparently would rather have everyone speculate about the reasons and wonder if it’s some kind of virus that will spread to other partnerships. You would think that if a change of ownership could trigger it, that would have happened months ago when CNET Networks merged with CBS (NYSE: CBS). A lot of emphasis is being made on TV.com’s newly competitive efforts to become a video destination. It’s hard to tell what role that plays, especially since the NBC Universal-News Corp (NYSE: NWS). JV was built on a split model of creating a portal and distributing the bulk of its content to competing portals. Meanwhile, at last check, TV.com continues to promote shows users can’t watch—without an explanation.

Update: A little more clarity although not from anyone who can talk on the record and not confirmed by Hulu or CBS—sounds like the material change Hulu is claiming is related to the TV.com relaunch. From one perspective, it’s an effort to push CBS towards including its own content in a re-configured deal with Hulu. More as warranted.

• Updated: Hulu’s Content No Longer Available On CBS-Owned TV.com; What About Other Partners?