Partial Source: Pwinsider
Here are the latest details on Justin Gabriel and his decision to ask for his WWE release. On the Raw prior to the Royal Rumble, Gabriel showed up to the arena and asked what his role would be on the show that night. WWE officials informed him that they had no plans for him. Gabriel then reportedly left the building, went site seeing, and returned to the arena later in the day. He once again asked about plans for the evening, and was again informed that they had no plans for him.
At that point, Gabriel reportedly made the decision that he no longer wanted to be with WWE. He left the arena, not telling anyone, and booked a flight home. While waiting for a connecting flight, Gabriel received a phone call from WWE Talent Relations head Mark Carrano. Carrano asked Gabriel where he was and told him that there were plans to feature him in a segment on Raw that night. Gabriel told Carrano he had left the arena and was quitting WWE.
WWE officials were not happy with how he chose to quit the company, but granted him his release prior to the Royal Rumble PPV.