We finally have a story about someone in the Manning family. Except it's not that Manning.
Manning had a $10.75 million base salary due next season but he reduced that to $1.75 million in base salary and took the remaining $9 million as a signing bonus. This allows the signing bonus to be pro-rated over the final years of the deal, creating more cap space for the Giants.
Teams often restructure contracts like this to create more cap space but it occasionally creates issues down the road as Manning will now have a higher cap number next season.