Peterson will be the free call up, as he is not currently on the roster. Then they will leave him on the roster, as he is in the rotation until Carrasco returns. This will require the Mets to drop a reliever on Sunday. They will probably drop two, as Hunter is scheduled to come off IL then. Probably Clay and Nogosek draw the short straws.
Nido may come back this weekend to replace Perez. Nido is on the COVID IL which does not require a minimum stay.
Bottom line is that there is no room for Vientos at this time. Davis previously had his roster spot, and now Ruf has it.
What will be interesting is when Escobar comes back from IL. They can't send Baty back down, can they? They may have to. The alternative would be to DFA Escobar with a year left on his contract. Not happening.