As an anonymous league member just pointed out Octávio Martínez signed the same exact deal.
One concrete contract rule strictly enforced is that any player with less than 5 years of ML service time will not be allowed to sign a contract extension of longer than 3 seasons. Additionally, any player with less than 5 years of ML service time may not be tendered an extension of longer than 3 seasons. Any contract found violating this rule will be nullified and will have to be renegotiated to fit within this rule. Teams that violate this rule will be penalized $10 million from their Bonus Funds.
Whether he signed it today or yesterday, being offered an extension before 5 years violates a concrete BBA rule.