Oklahoma and Texas have reached out to the SEC about possibly joining the conference, multiple sources confirmed to ESPN.
The Houston Chronicle, which first reported the story, cited an unnamed college official and said an announcement could come within a couple of weeks.
Both Texas and Oklahoma released similar statements on Wednesday, but officials at both schools declined further comment to ESPN.
"Speculation always swirls around collegiate athletics," a Texas spokesman said in a statement. "We will not address rumors or speculation."
Said Oklahoma in a statement: "The college athletics landscape is shifting constantly. We don't address every anonymous rumor."
A source told ESPN that Big 12 athletic directors and administrators are meeting Thursday evening to discuss the situation.
On Wednesday at SEC media days, Texas A&M athletic director Ross Bjork said he will be "diligent in our approach to protect Texas A&M."
"We want to be the only SEC program in the state of Texas," Bjork said. "There's a reason why Texas A&M left the Big 12 -- to be standalone, to have our own identity."
Texas A&M, along with Missouri, left the Big 12 to join the SEC in 2012.
Bjork said he and fellow SEC athletic directors had not discussed bringing Texas and Oklahoma into the conference. According to the SEC bylaws regarding conference membership, "a vote of at least three-fourths of the members is required to extend an invitation for membership," or in this case, 11 of the 14 schools.
Bjork also said he was unaware of any language in Texas A&M's deal with the SEC that would prohibit the league from adding another team from the state.
SEC commissioner Greg Sankey said he was worried about the 2021 season and didn't directly address what he described as a "report from unnamed people."
"I'm not going to comment on speculation," Sankey said.
Oklahoma State, while calling the reports "unconfirmed," said it would be "extremely disappointed" if they were true and would defend its position.
"While we place a premium on history, loyalty and trust, be assured, we will aggressively defend and advance what is best for Oklahoma State and our strong athletic program, which continues to excel in the Big 12 and nationally," the school said in a statement.
One potential obstacle for such a move, at least any time soon, is that Oklahoma and Texas signed a Big 12 grant-of-rights agreement, in which they granted their first- and second-tier media rights for football and men's basketball to the conference through June 30, 2025. That means the Big 12 would still own those schools' media rights for those sports -- even if they are no longer members -- until the agreement expires.
The Big 12's TV contracts with ESPN and Fox also expire in 2025. The Longhorn Network's deal with ESPN goes through 2031.
Texas A&M coach Jimbo Fisher said, "I bet they would," when asked what he thought about the possibility of Texas and Oklahoma seeking to join the conference.
"I just worry about A&M, you know what I mean?" Fisher said. "Listen, we have the greatest league of all. ... I don't know how I feel about it."
ESPN's Mark Schlabach and Heather Dinich contributed to this report.