Timeline: With Colorado Big 12 bound, here's how the college sports landscape has changed in the last 2 years

Colorado's decision to rejoin the Big 12 is the latest in a two-year flurry of moves that has reshaped the college athletics landscape.

It's hard to imagine the Buffaloes' move being the last, either. With nine remaining members, the Pac-12 could add more schools or others could leave. Heck, both could happen.

In case you've forgotten any of the major developments over the last 25 months, here's a quick refresher.

July 2021: An SEC bombshell

A report from the Houston Chronicle during SEC media days that Oklahoma and Texas are looking to leave the Big 12 for the SEC takes many in and around college football by surprise. Days after the report emerges, the two schools announce they are looking to change conferences. On July 29, the SEC presidents vote unanimously to expand the league to 16 teams and the board of regents at both OU and UT vote a day later to make the switch to the SEC starting in the summer of 2025.

August 2021: The Pac-12 stands pat

The Big 12 suddenly looks vulnerable to poaching by other Power 5 conferences without its two most recognizable football programs and just eight teams remaining. But the Pac-12 — the most logical conference to absorb some Big 12 teams — says in a statement it isn’t looking to expand. That opens the door for the Big 12 to be aggressive in looking for teams to add to the conference.

September 2021: The Big 12 adds four

Without any other conference looking to take any of its remaining teams, the Big 12 extends invitations to Cincinnati, Houston and UCF from the American Athletic Conference, and independent BYU. All four teams accept with an announced arrival date in 2024 as the Big 12 expands its reach from Utah to Florida.

October 2021: The AAC adds six

It’s the AAC’s turn to react to teams leaving the conference as it announces six teams will join the conference after Cincinnati, Houston and UCF leave. Charlotte, Florida Atlantic, North Texas, Rice, UAB and UTSA leave Conference USA for the AAC as the conference expands to 14 teams in both football and basketball. Meanwhile, Southern Miss leaves Conference USA for the Sun Belt along with Marshall and Old Dominion.

November 2021: Conference USA replenishes

Conference USA announces Liberty, Jacksonville State, New Mexico State and Sam Houston State will join the conference starting in 2023. Liberty and New Mexico State had been operating as independents, while the two other schools will make the transition from the FCS level to the FBS level. A year later, Conference USA announces Kennesaw State will join the conference in 2024.

June 2022: Big 12's new members can join early

The Big 12 announces its four new members will join in the summer of 2023 after the AAC announces it has reached agreements with Cincinnati, Houston and UCF to join the conference a year earlier than originally announced.

June 2022: UCLA and USC's stunner

June wasn’t just about the Big 12’s moves. At the end of the month, USC and UCLA break up the Pac-12 as we know it with their stunning announcements they’re heading to the Big Ten. Unlike the moves by Oklahoma and Texas, UCLA and USC announce their departures with just a year of warning thanks to the 2024 expiration of the Pac-12’s media rights agreement. The move to add the two Los Angeles schools also gives the Big Ten more leverage in its media rights negotiations as the conference ultimately signs deals with Fox, CBS and NBC for football game broadcasts starting in 2023.

July 2022: Big 12 says it's "open for business"

Big 12 commissioner Brett Yormark says ahead of his first football season as commissioner that “there is no doubt the Big 12 is open for business” when it comes to further conference expansion.

“We will leave no stone unturned to drive value for the conference,” Yormark said at Big 12 media day.

Pac-12 commissioner George Kliavkoff spoke at his league’s media day in the days following Yormark’s remarks and said the schools in his conference were committed to staying together before making a comment that looks more and more infamous by the day.

“They’re committed to the conference,” Kliavkoff said of the remaining teams. “I think the best thing to do is to ask them about it.

“With respect to the Big 12 being open for business, I appreciate that. We haven’t decided if we’re going shopping there or not yet.”

February 2023: OU and UT will leave Big 12 in 2024

Oklahoma and Texas announce they have reached a settlement with the Big 12 that allows them to leave the conference at the end of the 2023-2024 school year. The Big 12 will operate as a 14-team conference for the 2023 football season.

June 2023: SDSU tries and fails to leave the Mountain West

San Diego State tells the Mountain West it intends to leave the conference. The Pac-12 and Big 12 are seen as the only options for the Aztecs if they are moving to a Power 5 conference. However, an invitation from either conference never materializes and SDSU has to do an about-face weeks later and says it’s staying in the Mountain West for the time being.

July 2023: Colorado heads back to the Big 12

After a monthslong flirtation with the Big 12 and the Pac-12’s lack of a media rights agreement in place, starting in 2024, Colorado votes to move to the Big 12. The Buffaloes left the Big 12 in the first round of conference realignment in 2010 but will return less than two decades later as the Pac-12’s future continues to be murky without USC and UCLA.