Some aspects of baseball uniforms would look rather odd if people wore them around today, but were they common at the time that uniforms were first introduced? Were these standard everyday clothes or perhaps standard "athletic wear" for the time?
Some of the things I'm thinking are a little odd in the uniform:
The baseball hall of fame actually has a rather detailed website that has data for the uniforms used by many teams over the past 130 years: http://exhibits.baseballhalloffame.org/dressed_to_the_nines/introduction.htm
Nearly all of the information given below is from various parts of that website:
For the cap, the modern peaked-bill "ball cap" seems to have started with the Brooklyn Excelsiors in the late 1860s, but only to have become a common uniform element sometime around 1900. The modern prominence of baseball caps as acceptable headgear for daily casual wear seem to be a more recent development, possibly post-WWII.
The long jersey-style shirts were considered ordinary outdoors-wear at the time they were introduced in the 1880s. At some point in the mid-20th century the buttons were replaced with snaps, with different teams changing over at different times.
Interestingly, the stockings seem to have been adopted basically as a device for distinguishing one team from another given that lack of printed shirts or anything, sometime in the 1860s or 1870s. It was expensive to equip a small-time team with embroidered or printed jerseys and pants, but giving the whole team stockings of the same color and pattern was within the reach of even working-class ballplayers by the later 19th century.
That the batters knees was defined as the bottom of the strike zone may have reinforced this trend, as discussed in this newspaper article: http://articles.philly.com/2011-08-29/sports/29941646_1_pants-socks-cuffs
