I am a Referee Instructor. After watching the Seattle vs Colorado match, a student asked me if MLS does not follow Law 4 in dealing with undershorts. Seattle’s shorts are blue and yet several of their players were wearing knee length green sliding shorts and one player was wearing white. Since they were knee length, it was obvious even on TV that they were not following as we are teach. Not wanting to get into my opinion of the Referee, I answered that I was not intimate with MLS’ Rules of Competition and it could be waved in those. Can you clarify this?

USSF answer (July 26, 2010):
The requirements for the pros are precisely the same as those for all other players. This was an oversight by the refereeing team.