Obviously, he will age. He’s already started. Last year he stole just two bases, and he didn’t hit a triple. He’s unlikely to be an elite baserunner again, and he’s unlikely to maintain the extent of his defensive range in left field. But there are two things: one, Gordon shouldn’t hit the wall all of a sudden, and two, a lot of his defensive value is actually tied up in his arm, which has been the third-most valuable in the outfield of the past decade by both UZR and DRS.. I don’t know how outfield arms age, compared to range, but my sense is that they should age better....

We can do something really simple. The last four years, Gordon has been an outfielder worth 18.6 WAR. Over the last 30 years, there have been 23 outfielders worth something within 2.5 wins of that between the ages of 28-31. Between 32-35, those same outfielders averaged 12.5 WAR. These are just the simplest possible Gordon comps, but if you projected Gordon to be worth 12.5 WAR over the next four years, you’d expect him to sign a contract worth about $100 million.