Who's the pitcher?

[Little Jimmy]

This happened on another field this weekend and was talked about in the umpire camp. USSSA rules, but as always, all rule set info would be good.

#17 is the pitcher of record. At the beginning of inning 4, # 10 walks to the circle, picks up the ball, and throws 1 warm up. #17 now comes in circle to throw warm ups, but offensive coach argues that since #10 threw a warm up, she is now an unannounced sub and the new pitcher, and has to pitch to the first batter. Defensive coach says he was considering putting #10 in to pitch, but changed his mind and decided to keep #17 as pitcher.

There was a ruling on the field but before I say what it was I wanted to know what you thought. I think this has been discussed before but I can't find a previous thread.