Jordan Walker and the value of reaching the majors at age 20

A 'soft' historical survey of players who achieved the same

It’s been said often enough that even reaching the majors at an uncommonly young age is itself a potential indicator of looming greatness. Typically, we say this about those who crack the highest level while still in their teens – Bryce Harper, Ken Griffey Jr., Dwight Gooden, Mel Ott, to cite a few conspicuous examples. Before a swing is ever swung, it …