Someone made a post awhile ago and it was torn apart. This post is made a few times every year and gets torn apart. However, no team has ever actually tried it so who knows what the results would be. Personally, I don't think you can do this with your whole pitching staff, especially in the NL. However, with starters throwing fewer innings and most pitchers these days being 2-pitch guys, piggybacking is going to happen to some extent. I just can't believe it hasn't happened already.