MLB uses Atlantic League to test more rule changes
MLB Announces Experimental Rules To Be Tested During 2022 Atlantic League Season - The BayNet
MLB testing three new rules in Atlantic League, including designated pinch runner
Inside Baseball's Laboratory
5 MLB Rule Changes That Were Tested In The Atlantic Baseball League - FloBaseball
February, 2019
MLB is experimenting with more rule changes in the Atlantic League, including a “Designated Pinch Runner” - BlueJaysNation
MLB, Atlantic League announce rule experiments for 2023
MLB testing three new rules in Atlantic League, including designated pinch runner
MLB experimenting with moving back pitcher's mound as part of Atlantic League rule changes
Experimental rules for 2022 Atlantic League season