This happened last night and no one complained but I think I was wrong. ASA womens fastpitch. Coach says dp is going in for defo(who was pitching). After a few batters I realize that DP is actually playing left field and former left fielder is now pitching. Game ends a few pitches later.

I know that dp can play defense for any player but when dp subs for defo(the pitcher) does she have to go in at the pitching position? Did I blow that one even though no one noticed?

No, everything looks good to me. At no time is any player restricted to playing a particular position. There is only restrictions on positions a player cannot play whether the DEFO, DP or anyone else.

So then when coach says dp is going in for defo (whatever position) what it really boils down to is defo is sitting out and being subbed for?

Jimmy,
That is correct. Most folks run into trouble with the DP/DEFO when they try to make it more complex than it is. Break it down to one thing at a time and it is really a simple rule to understand and apply.

Steve M