I think Yermin stays down and Savala sticks.
Catcher is the position that is hardest for outsiders to actually judge and it's pretty clear that they don't think that Yermin is a big league catcher. When TLA talked about Savala's call up, he talked game planning and preparation with the pitchers. They way it was worded, I took that as an insight as to why they don't believe in Mercedes. More than any other position, catcher is the position where offensive contribution comes second.