You will need:
Sports stretch pants and matching shirt (get the colors to match your favorite team)
Padding for shoulders (soft foam, small pillows, or lots of paper towels formed to fit)
White knee socks
A. Dress your child in his stretch pants and matching shirt.
B. Stuff the shoulder padding under his shirt
C. Put the white knee socks on and the tennis shoes.
D. Place the helmet on (make sure he can see good, if not he can omit the helmet and just wear a baseball style hat that could even have his teams emblem on it)