There were many of us who were expecting regression from Pom, even if he stayed healthy, and positive regression from Price and Porcello. Sale is Sale. Therefore, the expectations were for ERod and Pom to be the #4 and 5 starters, in no particular order.
As far as the team being on a run for all time record books, the FO and Cora cannot make decisions based on trying to chase the record books. With the lead that we have over the Yankees, we can most certainly afford to give Pom another look. No, we cannot carry a negative producer in the rotation indefinitely, but I don't think anyone is saying that.