Why do baseball coaches wear uniforms?
Dear Straight Dope:
Why are coaches in baseball assigned a number like the players? What's the point anyways? And why do they wear a uniform at all? As far as I know, baseball is the only sport where this is the case...
Well, a little reading could have cleared this up, champ, but we'll be nice and lift the veil of confusion.
Let's hop in Peabody's Wayback machine, to the late nineteenth century, and examine the beginnings of organized sport in the United States. Basketball was invented by a gym teacher, who promptly set the standard for a coach who didn't participate in the game. Hockey and football also tended to utilize this sort of arrangement. In baseball, on the other hand, the "captain" was almost uniformly a member of the team until after the turn of the century. Most teams may indeed have had men serving as "manager," but their job was not to guide the team on the field; rather, the manager took care of travel arrangements and served more as a team's traveling secretary than anything else.
After the turn of the century, those guys who had formerly been captains of their teams, unwilling to depart from the game entirely when they were no longer capable of playing it, began to be sought after to manage the teams on the field. This would seem sensible, as these folks had years of experience with the nuances of the game, and leaving the decision-making to someone in the dugout allowed the players to concentrate on ... well, playing.
Apparently, the habit of wearing a uniform wasn't something the new managers were too keen on abandoning - so they didn't. The notable exception was Connie Mack, legendary manager of the Philadelphia Athletics, who in his later years never left the dugout. Why? Because in their infinite wisdom, the Lords of Baseball had decided that if it was good enough to be a tradition, it was good enough to be a rule. Mack liked suits. Baseball didn't like anyone not in a uniform on the field.
This rule, however, appears to be more of a league edict than a "rule." The only reference to such things in the official rules of major league baseball is a 1957 rule requiring coaches to be in uniform, specifically referring to first- and third-base coaches. I suspect the rule has been interpreted to mean any person whose presence on the field fills a coaching capacity; think about what a manager is doing when he goes out there. Considering that the team trainer and the grounds crew aren't in uniform, this interpretation seems pretty clear.
So, it all boils down to tradition, really. Now if we could just bring back doubleheaders, scorecards, pitchers batting in Cleveland, and the Brooklyn Dodgers, we'd be set.