Have You Been Pinned?

I always thought being pinned meant you were “going steady”, or maybe even a wrestling term, but hearing it used in this industry was a new one for me. So, I'm talking to a friend a while ago and she says to me “I just found out that Sara (not her real name) has a pin in her.” I had never heard someone say that to me before although I have seen headshots pinned on a wall at casting offices which I assumed were the ones being considered. And, of course, that's exactly what it means. Then just recently I'm talking with an acting coach and she starts telling me about one of her students who has been pinned 20 times this year (eyes rolling).... WOW! What a ride!