The team has two rookie pitchers in the rotation--Sproat, Harrison--and two other second-year starters--Misiorowski and Patrick.
Both of Sproat's outings have been caught by catchers other than Contreras, with neither of them going very well. (Acknowledge that the rainout double-header in Kansas City made one of those starts basically unavoidable.) While Harrison has thrown twice to Contreras, with good starts in both games.
Don't know if Drohan working with Sanchez behind the plate will be more like the Sproat outings or the Harrison ones.
Contreras definitely needs days where he's not catching. But perhaps trying to plan those days off that don't line up with the rookie pitcher starts might be something worth looking at going forward. Having a good veteran catcher to throw to would seem to be a benefit for a rookie pitcher. (Today is a spot start for Drohan, so it wasn't exactly planned out.)