So I am the AC and HC is gone (deer hunting) so I'm juggling the line-up and trying to keep same rotation he has been using. I call out the line up during one of our at bats and the girls get ready in order, I see girl step into box let her know she is swinging away then realize I have not substituted her in, I ask for time but the ump correctly denies my request as the pitcher is on the plate and getting ready to pitch. After the pitch she lets me know why she did not grant time which I acknowledge was the correct thing then I inform her of why I was asking for time, the girl at the plate was a substitute that I had not informed the umpire about. She states it OK and that it is a correctable error and I can now substitute her in and everything is OK. This is fall ball (ASA rules) and everyone is very laid back but it just did not feel right,was this the right call?