Lots of scenarios for the other three teams to join them, but the Big Ten confirmed Oregon is locked in.

https://www.espn.com/college-football/story/_/id/42491676/big-ten-confir...

Mod edit:  yeah, there’s an article on it.

https://www.elevenwarriors.com/the-big-ten/2024/11/150800/oregon-officia...