With our depth and Ball and Mahaney "incrementally" getting better on D, we should be fine - trend is directionally accurate.
What we need for Reed, Jr. to be effective is switching until the guy guarding him is a foot shorter....of course that needs the opponent to have a shorter/slighter wing who Reed, Jr. can just body past. With Georgetown, we didn't get that so Johnson, who has quicker feet than Reed, Jr. got more minutes and played decently well (as others have said, fouls have come down, rebounds up, etc).
But Kalkbrenner would have a field day with Johnson so we need Reed, Jr. in there.