I've been browsing through some historical pitching stats at Baseball-Reference.com. It seems that in the 1910s and 1920s, starting pitchers frequently pitched on 3 days rest, sometimes pitched on ...
Here is a video of Miami reliever Carter Capps pitching. As you can see, he basically jumps off the rubber, and delivers from the front of the mound. Apparently, MLB gave their approval to Capps's ...