@lines = ('Foo9 NA1234 blah blah blah',
          'Bar8 NA2345 blah blah blah',
          'Baz7 NA3456 blah blah blah');
foreach my $line (@lines) {
    next unless $line =~ m{^(\S+) NA(\d+) (.*)};
    my ($site, $userID, $data) = ($1, $2, $3);
    print "SITE: $site   USER: $userID   DATA: $data\n";
}