A lot of people don't trust speed-and-defense players to age well. They're one knee injury from being worthless! Once the speed goes, what's left?! Just look at what happened to Carl Crawford!
The skepticism over the value of non-hitting production is never more evident than when a player like Jacoby Ellsbury hits the free-agent market. Although some might grudgingly admit that Ellsbury -- who turned 30 in September and just completed his age-29 season -- has had a couple of terrific seasons lately, his lack of power and dependence on his legs have created some doubt about whether he'll be an impact player for much longer.
Is such skepticism actually warranted, however, or simply another instance of hitting being overvalued relative to other skills? Rather than just lean on conjecture, let's look at how players with similar skill sets and performances at Ellsbury's age have done after they turned 30.