Brandon Austin is working out with the Philadelphia 76ers this week, per NBA sources, trying to revive a basketball career in limbo after sexual assault allegations at two colleges -- Providence College and the University of Oregon.

Austin's effort to begin his NBA career has been facilitated by a secret arbitration ruling, meted out in October and pertaining to two players -- Austin and one unnamed player -- who have faced sex assault or domestic violence allegations, according to sources familiar with the ruling.

Women at both schools accused Austin of sexual assault, including participation in an alleged gang rape at Oregon in 2014. At Providence, Austin was suspended from the basketball team, and at Oregon, he was dismissed from the program and banned from campus. Austin was never charged with a crime. (The alleged victim in the Oregon case later sued the university over its handling of the case, and won a sizable settlement.)

Police brought the other player involved in the NBA arbitration ruling in for questioning after being called to the scene of an alleged domestic violence incident, but he was never charged, sources say.

Last summer, the league sent a memo to all 30 teams instructing any team interested in signing either player to call the NBA office, sources say. Teams that called were told about the allegations, and that the players could face discipline -- including suspensions or fines -- in the event any team signed them, sources say. No NBA or D-League team did.

The National Basketball Players Association filed an arbitration claim arguing that the memo had a chilling effect, and that the league had overstepped its bounds by telling teams it could discipline players for past allegations, sources say. The arbitrator agreed with the union that the league could not fine or suspend the players going forward based on prior allegations, sources say. The league sent teams a follow-up memo clarifying that after the ruling.

The arbitrator upheld the league's authority to "disapprove" entirely any contract any player might sign based on the NBA commissioner's broad authority, outlined in the league's constitution, to determine that "all players shall be of good moral character." The arbitrator also rejected the union's claim that the memo amounted to a form of collusion, sources said.

In sum, the arbitrator ruled the league could reject any contract upon its proposed signing, but that once the players were in the league, they could not face further discipline due to prior allegations against them, sources say.

The union shared the results of the arbitration at seminars with player agents in recent weeks.

Critics charged the league with being too lenient on domestic violence in 2014, after the emergence of video showing NFL star Ray Rice violently beating his fiancée in an elevator and a string of incidents in which NBA players charged with domestic violence faced minimal discipline.

The NBA to that point had preferred to wait for a criminal conviction or guilty plea before imposing discipline. Many cases never reached that stage. The union argued in the October arbitration case that other players who had faced similar allegations were still in the league.

The league promised to rethink domestic violence policy as part of negotiating a new collective bargaining agreement with the players' union. In the interim, the league suspended Sacramento point guard Darren Collison (for eight games) and former Charlotte forward Jeffery Taylor (for 24 games) after each pleaded guilty to charges related to domestic violence incidents. Michele Roberts, executive director of the players' union, said at the time that the length of Taylor's suspension ran against precedent, and that the NBA may have bowed to public pressure in the wake of the Rice video's release.

The new CBA, which takes effect in July, confirms the NBA's authority to conduct investigations and impose penalties for acts of domestic violence -- subject to challenge from the players' union -- before the resolution of any criminal case. It also creates a more comprehensive overall preventative policy that includes counseling for players and their families; training seminars; and a hotline players and their families can call at any time.

The CBA also calls for the creation of a "policy committee" composed of league and union representatives, plus independent experts, to oversee treatment for players who have been subject to discipline or criminally convicted. The committee is also available to players on a voluntary basis. The committee will craft treatment plans an alleged offender must abide by that might include counseling or psychological testing.

The commissioner can also place players on paid administrative leave while an investigation into domestic violence is pending. The policy applies not only to domestic violence, but also to sexual assault and child abuse.

The arbitration ruling is reminiscent of the Dante Cunningham case from 2014. Police charged Cunningham in a domestic violence incident, but eventually cleared him and concluded the alleged victim fabricated some of the allegations against Cunningham, according to The Associated Press.

Despite the judicial vindication, teams steered clear of signing Cunningham for several months, and Cunningham worried potential suitors feared any backlash that might come from signing him, per AP.

At the time, Roberts expressed concern about how the league and its teams would handle the delicate balance between punishing abhorrent alleged conduct and jumping ahead of the criminal justice system.

"I don't, quite frankly, know what the rush is," Roberts told the AP then. "Many of the teams are saying, until this is resolved I'd like at least for you to not play. I'm not fond of that."

The league and union declined to comment on the arbitration.