The University of Nebraska is prepared to join the Big Ten, a source close to the program told ESPN’s Chris Mortensen.

The source said a move will likely be announced Friday, which is the final day of an ultimatum reportedly issued to the school to either leave the Big 12 or stay put. The move is also expected to trigger a larger six-team stir in the Pac-10.

“A source with knowledge of the Big Ten’s plans confirmed to ESPN.com that Nebraska will join the Big Ten by the end of the week or early next week. The source said the formal process of accepting a candidate either has started or would be under way shortly, as Nebraska must formally apply for admission to the Big Ten.”

If Nebraska announces a move to the Big Ten, the Pac-10 appears ready to make a move on six Big 12 teams; Texas, Texas A&M, Texas Tech, Oklahoma, Oklahoma State and Colorado.

ESPN is reporting that Colorado, who has been jockeying this week with Baylor to become the final Pac-10 selection, has received an invitation to join the conference.

It remains unclear whether the addition of Nebraska would cease Big Ten expansion.

However, ESPN reported that Missouri is off the Big Ten’s radar as the conference focuses on Nebraska.