At the time of writing, Philadelphia's return in the deal is not known, but with the anchor of a contract attached to Hayes, it shouldn't be much.
The Flyers will likely be retaining a portion of the contract, which pays him just over $7M annually, according to David Pagnotta. Once thought to be a staple offensive piece in the top six for the Flyers, Hayes has struggled, only notching 54 points in 81 games this season.