As somebody noted in an earlier post, the rules for North Americans and
Europeans are different.  A North American player can only be drafted in the
window when he is 18-20 years old.  He becomes a free agent if he is undrafted
in this window.  Europeans must have been drafted to play in the NHL.  However,
there is no maximum age restriction to be drafted.  The Minnesota Wild took a
couple of "old" Europeans (I think one was 31 years old) late in the draft this
year.