The outcome was predetermined:
1. Arbitration was presided over by the NFL’s unilaterally-designated, partial arbitrator with long-standing professional and economic ties to the League as the former head of Respondent NFL Management Council;
2. Henderson then denied the most essential evidentiary requests made by Elliot, including its request for access to critical and exculpatory witnesses and documents;
3. NFL was exposed for trying to suppress Roberts’ conclusion, after reviewing all of the evidence and interviewing Thompson six times,
4. The League’s investigation had accumulated insufficient evidence to overcome Thompson’s credibility problems and discipline Elliott; and
5. Henderson has never, in his history, completely overturned a Commissioner suspension.
So, yea Elliot was left with no option other than filing a petition to vacate the arbitration ruling before Henderson rubber-stamped Goodell's six-game suspension.
Elliot faced an impending threat of an imminent and adverse outcome.
Based on the above points, it was logical that Elliot would face harm and imminent threat to his career absent filing the petition.