The rules may be different in other places, but in general once the pitcher is taken out, he/she can not return to pitch. He/she may play anywhere else, but generally they can not come back in to pitch

No. In Little League (12U), a Pitcher can not return to the mound. Only in the divisions ABOVE Little League; Junior League, Senior League, and Big League. Can the pitcher return. You can go to the Little Legaue website and search under 2009 rule changes. Regulation VI - Pitchers (b)