As a team, Cleveland's defensive rating has went from 104.1 regular season to 99.6 postseason. Now, some of that is teams being allowed to be more physical in the postseason. But Dellavedova's increased minutes would seem to have played some part in that as well. I don't know how good Dellavedova is on defense in general. I thought he was average at best the times I saw him in the regular season. But let me say a few things:
1. Irving (like Lillard) is a well known defensive liability. And I'm guessing that fanboy chimed in without realizing that.
2. Besides, Kawhi Leonard, Dellavedova has played the best defense on Curry that I've seen anybody play on him in the regular season and playoffs. Now, I don't believe that means he's suddenly a great defender. It just means he's had a nice little stretch of games. But it has been aided by Curry being cold from the field in a way that he hasn't been all year long; so yea, I'm sure Dellavedova may be getting a little two much credit.
3. Dellavedova's defense is a distant second to Kawhi Leondard. Had the Spurs played the Warriors, that series would have likely went to the Spurs.