The soon-to-be free agent's age is a bigger deal than you think, because drugs.
Anabolic steroids and all their PED friends do more than just bulk guys up so they can jack more dingers. They reduce the bounce-back time needed after exhaustion or injury. That's especially useful for older players, whose bodies wear down more easily and take longer to recover. It's important to remember that as we consider how much the Cardinals should pay for a long-term contract for Jason Heyward.
The first six years of a player's career are controlled by his team (including arbitration).