The Big 12 athletic directors wrapped up two days of meetings in Dallas on Wednesday and Neinas met with each individually.
Missouri is the latest Big 12 school in the spotlight, considering whether to stay in the conference or move to another league.
The Big 12 has already lost Texas A&M to the SEC.
Last week, Oklahoma President David Boren said all nine remaining schools had agreed to grant their top-tier television rights to the conference for six years.
Missouri Chancellor Brady Deaton wouldn't go that far, saying members would pursue that deal.
"We understand that relative to the grant of rights issue this matter has to be considered by the Missouri board of curators, and they will have an opportunity to review what the conference has accomplished, what we're doing and what we plan to do," Neinas told reporters on a conference Wednesday night. "I think that once they have an opportunity to fully understand and comprehend what the conference is doing that they will agree that Missouri should continue to be a good member of the Big 12 Conference."
"I think it depends upon the institutional process each member is required to follow," he said. "And it would not only just apply to the University of Missouri. It would apply to other institutions as well."
He also said he did not know of any offer to Missouri from another conference.
"I have not been contacted by anyone from the Southeastern Conference," he said.
Neinas suggested that Missouri would probably miss its century-old Border War football rivalry with Kansas and the opportunity to play its conference basketball tournament regularly in Kansas City, Mo., if it decided to switch leagues.
"So I think there's a lot to look at," Neinas said. "You know what happens is a pretty girl walks down the aisle and you say, 'Boy, I'd like to take her to the prom.' But there's also one who's tried and true and you know is going to be there."
Neinas was the commissioner of the Big 8, which became the Big 12 in 1996 after Texas, Texas A&M, Texas Tech and Baylor joined.
Regarding possible expansion of the Big 12 — with or without Missouri — Neinas said there was still no telling how many schools might be added. The presidents of Oklahoma and Oklahoma State have said they are most comfortable if the league gets back to 12 members, while Texas athletic director DeLoss Dodds advocated 10. Neinas said there was even some sentiment for staying at nine.
"There is no unanimity at all. There isn't even a plurality among the athletic directors as to what they would like to do," Neinas said.
He added, "There has been no shortage of interest" from teams wanting to join the conference.
"We would hope we would not be at eight," Neinas said.
Neinas had said last week that there was "resistance" from some existing members to adding teams from Texas.
"I'd say that's changed," he said.