The SEC is now going to nine conference games, starting in 2026, as has long been discussed. The Big 10 and Big 12 have been at that point for quite some time, but the SEC, thanks to their depth top-to-bottom, has not really needed to— they still routinely top the strength of schedule metrics year in and year out.
This move, though, heralds a likely shift in the format for the College Football Playoff in the upcoming years. There's been a lot of change on that front in the last few years, and it looks like such shifts are far from over.