"In a two-year contract, neither season can comprise more than 60% of the total value of the contract. In a three-year contract, no season can comprise more than 40% of the total value of the contract. In a four-year contract, no season can comprise more than 30% of the total value of the contract. In a five-year contract, no season can comprise more than 25% or less than 10% of the total value of the contract. There is a maximum allowable offer of $20 million for any season. The minimum for any season is the minimum annual salary at that level. For the big leagues, this is 325K. "
When you are on the player's negotiation page and hit help, you will be able to refer to this guideline.