Are there any managers who never played professionally at all? Bill Belichick, for instance, never played in the NFL or even at a major college, though, coach's kid at Navy. About half the coaches in the NBA never played in the NBA. Obviously baseball is different in that even a career minor leaguer is a pro.
Anecdotally it seems like you have that cliche/pattern where the less accomplished/talented players make the best managers. Along with the catchers.
Some of this is is obviously due to changes in the analytics era but also I feel like it stands to reason that a lot of minor league coaches and managers and major league coaches never played in MLB, and are often potential managers. Long and Dickerson, for instance (Wathan did get to the majors, barely).