Jerseys worn outside

[Jimgolf]

If it looks like a normal jersey, have 'em tuck it in.

Jerseys that are meant to be worn outside are shorter than normal jerseys and usually have a border or other design device near the bottom of the jersey. As was pointed out, they may also have a V notch on the side.

You'll know them when you see them. Having the size label on the inside is not usually enough.

Just remember that the very fabric of the universe depends on basketball players keeping their jerseys tucked in. Be ever vigilant.