A variety of OSU sources, as well as Castiglione, continue to say they've had no talks with Pac-10 officials.
OSU released a statement late Friday reaffirming that nothing has officially changed for the school.
"As we noted yesterday, we will need to evaluate our options and opportunities in light of today's announcement by Nebraska and Colorado's announcement yesterday," OSU spokesman Gary Shutt said in the released statement. "Our desire has always been to keep the Big 12 Conference together, and we have worked toward that end alongside several other Big 12 institutions.
"We are pleased Oklahoma State University has opportunities and we believe it is a reflection of the strength of our overall athletic and academic programs."
The Austin American-Statesman reported Friday that, according to a "highly placed official from a Big 12 school," OU, OSU, Texas and Texas Tech will join the Pac-10 once formal offers are made to them.
The official told the newspaper that Texas A&M has 72 hours to decide whether to accept the Pac-10's offer, and that official offers could be made over the weekend.