When you add a created player to a roster, the lineups will automatically be reordered so the other player you are referring to may have been placed on the inactive list. To correct that problem, you just need to go to the Reorder Roster menu and change the lineup for your team.
I've responded to your post in the other threads. In future, please don't post the same question in multiple threads. Thanks, and welcome to the Forum.
There's no need for that kind of attitude. I was talking to costa_rica9 who posted the same question in another thread in addition to bumping this one. I realise your question was already answered, having posted an answer myself.