In order of most acceptable to least acceptable
  1. He died
    It would be really difficult to post grades if you died.
  2. He got fired
    If I got fired, I wouldn't want to post my students' grades either.
  3. He was exiled
    Can you even get exiled from the United States?
  4. Still upset about Abby Wambach retiring
    Considering his comments on women in sports consisted of a rant of questioning why college volleyball players were wearing little black dresses in their media guide, this is unlikely.
  5. He got sucked into a sinkhole
    What's the correct terminology here? Sucked? Sunk? Fell into? These actually happen where I go to school, so it's possible.
  6. He went to Chipotle and got norovirus
    He doesn't really seem like a Chipotle kind of guy, but you never know.
  7. He doesn't know how to use the Internet
    Probably the most likely and least acceptable