NFL contracts are laiden with incentives and bonuses. There's percentage of snap bonuses, pro-bowl, other statistical bonuses. Then guaranteed vs. non-guaranteed money. There's also the franchise and how they treat the players both in-season and out of season. OTA activities. Some teams almost always makes players restructure their contracts. Others are notorious for cutting players on any team friendly deal.

Such an oversimplification and complete lack of understanding to just state, Player A is greedy b/c he took $3 million more. Every non-minimum NFL contract is complex with multiple contingencies and moving pieces.