NHL deputy commissioner Bill Daly has suggested that the Ottawa Senators may have solid grounds to file a grievance with the NHLPA or Dany Heatley himself based on the fact that Heatley's trade demand may have compromised the contract signed, according to Sportsnet.
The grievance may be as simple as having any team which acquires Heatley (if he ever agrees to the trade that he demanded) to reimburse the Senators the $4M already paid to Heatley. It's unclear if a more significant grievance, such as one directly against Heatley, would be possible.
The cost which Heatley's demand and subsequent waffling has extended far beyond the $4M bonus paid to Heatley on July 1. When the demand was made public, it immediately lowered Heatley's trade value on an already timid market. When he refused to waive a trade to the Edmonton Oilers (and possibly other deals-in-principle that may have not come out), he did no favours to the Senators nor the Oilers. His uncertainty cost the Senators an opportunity to pursue other free agents, some of the best of whom are now off the market.
If those are grounds for a grievance directly against Heatley for significantly hampering the Senators' ability to ice a good team is uncertain, but even if the Senators did take such an avenue, it may be negative overall. A team that takes a player to court, no matter how extreme the circumstances, might not appear to be the top choice for players looking for new contracts.