The Big Ten has begun exploratory discussions about expanding membership to 18 or even 20 teams, industry sources have told Yahoo Sports. The schools being considered are Oregon and Washington if the league adds two schools, and Cal and Stanford if it wants to move to 20. All four institutions are currently members of the Pac-12.

The discussions are in the very early stages, sources caution. No decision, including on whether to expand or stay put at 16 teams, has been made or is considered imminent.

The Big Ten may also patiently wait to see what happens with other Pac-12 schools and their potential move to the Big 12 before acting at all.

However, ballooning the league to as many 20 teams by adding a six-team West Coast flank — including 2024 arrivals USC and UCLA — is a real possibility. This is especially true if the Pac-12, which dates back to 1915, falls apart in the near future.

A group of four Big Ten university presidents began the preliminary process on Wednesday. The day prior, Pac-12 commissioner George Kliavkoff presented a media rights package to his membership that was heavy on games appearing on an Apple TV+ subscription streaming service. Revenue estimates were as low as $20 million per year, per school.

By comparison, Big Ten schools will receive a minimum of $50 million a year with games mostly appearing on linear television — CBS, Fox and NBC. That number is expected to grow annually. Meanwhile, the Big 12 has a $31.7 million per year package for schools.

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Last week, Colorado voted to leave the Pac-12 for the Big 12 starting in 2024 without even hearing Kliavkoff’s long-delayed offer. After the presentation, speculation ramped up that Arizona would follow, with Arizona State and Utah potential flip options as well.

With the Pac-12 at risk of splintering, Oregon, Washington, Cal and Stanford renewed their push to the Big Ten, seeking a safe, and far richer harbor, for their athletic programs starting in 2024.

The Big Ten has been reluctant to move to 20 teams, even if many in college athletics believe expansive superconferences are inevitable. One reason has been a hesitancy to deliver the final destructive blow to the Pac-12, although the poaching of UCLA and USC caused massive destabilization.

The Big Ten was, for generations, Midwestern-based with a like-minded membership. The modern realities of college athletics though is to go bigger in search of marquee matchups featuring big branded teams that can draw millions of viewers.

The Big Ten’s thinking is that if the Pac-12 is going to be decimated anyway with the departure of Arizona, Arizona State and Utah, and 20-team national conferences are the future, then why not act now when the conference is already in transition? It could just add Oregon and Washington, but at that point, why not bring along Cal and Stanford?

In 2022, the Big Ten agreed to a seven-year, $8 billion media rights deal with Fox, CBS and NBC. Part of the decision will be based on whether those broadcast partners are willing to offer a pro rata share — or something close — with the addition of four more schools.

The move would give the Big Ten control of the West Coast, especially California, as well as open a new television window with games played in prime-time out West and late night in the East.

Oregon and Washington have fielded strong football programs in the past and have excellent fan bases and markets in Portland and Seattle.

Cal and Stanford have been less successful of late, but bring the massive Bay Area not just for football viewership but in attracting potential students and connecting with corporate partners and alumni. All four schools are members of the prestigious Association of American Universities.

The downside is simply getting too big, too fast. Additions would dilute the amount current members play each other and threaten regional rivalries. Then there is just the logistics of an unwieldy league that stretches from Southern California, to the Pacific Northwest, through farm lands and Midwestern cities all the way to the edge of Washington D.C. and New York.

One source tossed out the possibility of playing the Big Ten championship game some years in the Rose Bowl in Pasadena, California, rather than Lucas Oil Stadium in Indianapolis. Also a possibility is a more regional based setup for so-called Olympic sport travel.

If the Big Ten is willing to work through the details, then this deal will get done. The four Pac-12 schools will jump at a membership offer.

If so, the remaining of the so-called four-corner schools — Arizona, Arizona State and Utah — would almost certainly leave for the Big 12, making that league 16 teams strong. They may do it even before the Big Ten acts.

That would be a bitter development for the current Pac-12 members left behind — Oregon State and Washington State. They would likely join the Mountain West Conference or to maintain the Pac-12 brand and merge with any number of MWC schools.

Both schools have proud fan bases, but limited market share due to geography and other factors.

Unknown is if the SEC, which will move to 16 teams by adding Texas and Oklahoma in 2024, would consider a counter-move to its Midwestern rival and go to 20 schools strong. A number of ACC schools are desirable, but those schools are believed to be locked into a grant-of-rights deal that runs until 2037.

Then there is Notre Dame, a proud independent who could finally feel pushed to join a league full-time.