The NCAA Board of Directors released a statement Tuesday in an effort to explain the denial of some transfer waivers for student-athletes after North Carolina officials publicly admonished the institution after it denied a waiver for wide receiver Tez Walker.

The NCAA says it is aware of some committee members involved in regulatory decisions that have been threatened and are cooperating with law enforcement.

Walker started classes in January at UNC and the NCAA, at the time, said it would be denying waivers for two-time transfers.

In the statement, the NCAA claimed that transferring multiple times "slows student-athletes' progress toward a degree, especially with those who transfer later. It stands to reason that multiple transfers would further slow time to a degree," and that "citing extenuating factors, such as mental health, does not necessarily support a waiver request but instead may, in some situations, suggest a student-athlete should be primarily focused on addressing those critical issues during the initial transition to a third school."

The NCAA said 21,685 student-athletes entered the transfer portal this year.

UNC has said that Walker wanted to be closer to home in North Carolina and had mental health challenges at his previous school, Kent State.

North Carolina football coach Mack Brown was one of many who did not like the decision on Walker and the school's board of trustees met this week in an effort to help Walker, including pursuing possible legal action.

"I don't know if I've ever been more disappointed in a person, a group of people or an institution than I am with the NCAA right now. It's clear the NCAA is about process and couldn't care less about the young people it's supposed to be supporting," Brown said.

"Shame on you, NCAA. SHAME ON YOU!"

The Board also took issue with Brown and other North Carolina officials who spoke out, as well, saying they were "troubled" by their remarks.

"Those comments directly contradict what we and our fellow Division I members and coaches called for vociferously – including UNC's own football coach," the board said.