IEL of the World Cup

As the world's most exciting sports event begins, I was hoping to conjure up a link to IEL.  How about this.  National teams are limited to nationals.  The team administrators obviously discriminate in the national treatment sense against foreign players.  Would this violate a GATS commitment in the relevant sector, assuming for a moment that the players are service providers under Mode 4?  The first answer is, "it's not a measure," at least to the extent that the teams are private.  But would it be a measure to decline to enforce otherwise applicable national laws against employment discrimination on the basis of nationality?  Would it be a measure to carve out an exception to those laws?  The second answer is that it does not violate national treatment, or that it is not "less favourable," if there is a a non-protectionist type of reason for the differential treatment.

I don't want to be a spoil-sport (so to speak), but just thought the blog should get it on the World Cup hype.  For some international relations-soccer links, see this Council on Foreign Relations site.