According to a source familiar with this week's appeal hearing of Ezekiel Elliott's suspension, Kia Wright Roberts, the NFL's director of investigations, testified Tuesday that she was the only NFL employee who interviewed the running back's accuser, Tiffany Thompson, during the investigation and that she would not have recommended discipline for Elliott based on what she found.

Roberts further testified, according to the hearing transcripts, that she was not included in the part of the process where the committee that investigated the Elliott matter recommended discipline to NFL commissioner Roger Goodell.

As a result, the NFL Players Association believes it has a strong case for challenging Elliott's suspension based on what it perceives as serious flaws in the NFL's investigative process, the source said.

On Wednesday at the hearing, appeals officer Harold Henderson heard testimony from Lisa Friel, the former New York City prosecutor who now investigates domestic violence cases for the NFL. Friel's testimony corroborated that of Roberts, and the part of that testimony with which the NFLPA took issue was that Goodell imposed the six-game suspension without Roberts' input with regard to appropriate discipline.

Roberts was part of the committee that wrote the 160-page report on its investigation into Elliott's case, but that report did not include a specific recommendation of discipline. A different committee, which included some but not all members of the original investigating group, met with Goodell to discuss discipline based on the report. Roberts was not asked to be part of that meeting, according to her testimony and that of Friel.

As a result, the union concluded that the process by which the NFL arrived at a six-game suspension for Elliott encountered significant flaws somewhere between the investigation itself and the ultimate decision to suspend.

The concerns about the NFL's investigative process in this matter could form the basis for a court challenge aimed at getting Elliott on the field for the Dallas Cowboys' Week 1 game against the New York Giants. If the union files a suit seeking an injunction that would vacate the suspension, Elliott could potentially be allowed to play while the case is working its way through the courts.

A similar situation developed two years ago, when New England Patriots quarterback Tom Brady's four-game Deflategate suspension was overturned by a court just before the start of the 2015 season. Brady was allowed to play the entire season, before a higher court reaffirmed the suspension the following offseason and Brady had to sit out the first four games of 2016.