The grand jury also indicted two of Mitchell's sons, six other men and a Costa Rican company. The trial is set to begin in April in federal court in Oklahoma City.
Mitchell's defense attorney, Scott Adams, confirmed Tuesday that Parmley was a client of Mitchell.
Adams told The Oklahoman on Sunday that Mitchell “on the bookmaking aspect of it ... was just simply telling people to go on a particular website over in Costa Rica that in our opinion was legal.”
Adams said Tuesday, “It was all legal. Every bit of it was all legal.”
Oklahoma City Assistant U.S. Attorney Bob Troester said prosecutors would have no comment beyond what is stated in legal filings at this stage in the proceedings.
TU President Steadman Upham announced Parmley's suspension about 4:15 p.m. Tuesday.
“TU Athletic Director Ross Parmley has been placed on administrative leave pending further investigation into allegations of gambling,” Upham said in a brief statement. “In the interim, Executive Vice President Kevan Buck will be acting athletic director.”
The NCAA opposes all forms of legal and illegal wagering on college sports. The NCAA claims sports wagering “threatens ... the integrity of the game.”
The NCAA said its rules prohibit athletics department employees “from wagering on intercollegiate, amateur and professional sports in which the association conducts championships.”
The suspension comes as TU prepares to host the Conference USA football championship game Saturday.
Parmley was athletic director for the Norman Public Schools before coming to work at TU in 2005 — at first as the director of football operations.
His other positions at the university included a few years as the associate athletic director for operations and administration. He was the interim athletic director for three months before his promotion in January.
He is a native of Lawton, according to the university's website.