Sooooooo PSA: they made it easier to drop from the bottom division of a tier lol
Just dropped from gold 4 to silver 1 with silver 1-silver 2 MMR (both teams full of silver 1/silver 2 players). In the past to drop from gold 5 to silver 1 you would need silver 4-silver 3 MMR (you would essentially drop once you started to see one or two silver 4 players in your game if you kept losing).
So. PSA. This season if you want to maintain your rank for rewards, it's probably best to play normal draft.