This Eugene Register Guard report states that the U of O gave Matthew Halls a pay raise and a new four-year contract in June before firing him in August. So something went very sour in a hurry.
And now this report from The Telegraph in the UK. If that is true, then the matter should be cleared up and Halls reinstated. Note that Bob Keefer in the Eugene Weekly had mentioned the same gossipy incident as a possible reason.
A thank you to Mark Mandel for alerting me of these articles (including the earlier ones in the Eugene Weekly).