Possibly the most important battle lines in Big 12 expansion have been drawn: quality football vs. quality ratings.

The SportsBusiness Journal reported on Monday that ESPN and Fox are "pushing back" against Big 12 expansion because the schools being mentioned as the most likely additions will make the league less valuable.

The networks claim the likes of Houston, UConn, UCF and Memphis would "water down" the Big 12, which isn't exactly news.

That ESPN and Fox are reportedly advising against expansion is the new development. The two networks are bound by a clause in the current Big 12 contract to pay pro rata -- or equal current value -- to any teams added to the league.

It is widely accepted that any combination of teams currently under consideration makes the Big 12 worse at football. Apparently, ESPN and Fox believe that dilution would carry over to the revenue side, too.

The existing Big 12 deal is worth $2.6 billion over 13 years. After paying all that money, ESPN and Fox need to make it back in terms of cable subscription fees and advertising revenue. Oh yes, and high ratings so it can ramp up those figures.

New inventory loaded with a lot of Cincinnati-Kansas State and Iowa State-UCF games probably isn't desirable to the rights holders.

The College Football Playoff basically caved to that ratings pressure last week. The CFP announced all national semifinals going forward would be played on Saturdays and holidays.

ESPN paid $7.2 billion to televise the CFP for 12 years. Ratings for the semifinals plunged 36 percent last year when they were played on New Year's Eve. Originally, the CFP was steadfast in saying the semifinals would stick to weekday New Year's Eve games with CFP executive director Bill Hancock terming the ratings drop a "first-world problem." ESPN played a major role in getting the CFP to pivot on that position.

The basic question: Does the Big 12 care about angering its rights holders in future negotiations? Even with Texas and Oklahoma as Big 12 members, those rights holders might not be willing to pay as much for a league that includes, for example, BYU, Cincinnati, Houston and Memphis.

In the history of modern conference realignment, only two Group of Five schools have gotten invites from Power Five leagues -- Utah in the Pac-12, TCU in the Big 12.

The Big 12 could be adding four Power Five schools at once. Texas (No. 2) and Oklahoma (No. 8) are both in the top 10 in athletic department revenue, according to the USA Today database.

The eight schools most commonly mentioned in Big 12 expansion are ranked between 48th (UConn) and 70th (Colorado State). BYU is not listed in the database because it is a private institution.

Big 12 teams are making $30.4 million in revenue each year, commissioner Bob Bowlsby announced in June. That figure could increase to $43 million per team when the contract expires in 2024-25. Such contracts are typically back loaded.

If the Big 12 expanded by four teams today, the league could be in for a $1 billion bonanza.

The Big 12 already has gone to the two rights holders to pay an additional $30 million per year for a league championship game beginning in 2017.

Activating the pro rata clause, which SBJ termed a "cash grab," rubs "ESPN and Fox the wrong way because any new schools would not carry the profile of most Power Five schools ..."

SBJ suggested the issue could eventually result in a court battle if the two media giants decide not to pay.

Bowlsby was adamant about the pro rata clause when the expansion process was announced two weeks ago.

"We intend to exercise the full prerogative of what we negotiated," the commissioner said. "I don't think we have to make apologies for stipulations we both agreed to."

In a sense, the networks can't be blamed. In a show of good faith, ESPN and Fox agreed to pay the Big 12 the same money when it was reduced to 10 teams by conference realignment in 2010.

At the time, the general industry conclusion was that any league that included Texas and Oklahoma was worth saving.

In the current deal, Texas and Oklahoma are bound to the Big 12 through 2024-25 by a grant of rights. If either school leaves, its television rights would be retained by the Big 12.

However, it's possible new members would not join until the 2018 season. At that point, there would be only six years left in the current deal. That's a blink of an eye in the rights fees business.

Depending how soon four expansion teams would be phased in to the Big 12, the existing 10 teams could be in for a windfall. They would pocket the difference in revenue while new teams are phased in.

For example, both TCU and West Virginia just received full Big 12 shares for the first time in this, their fourth year of conference membership. Rutgers and Maryland are in the middle of a six-year integration that won't allow them to get a full Big Ten revenue share until 2020-21.

The Big 12 announced July 19 announced it was exploring expansion by two or four teams. CBS Sports reported last week the process might be completed by the beginning of the season.