Dare
Chairman of Selectors
In my opinion only injured players should be replaced. People now know that they can take chances on selecting some players because if they don't play they can be replaced.
There also needs to be solid evidence that the player is injured. In the recent New Zealand vs Bangladesh ODIs some people were asking for Butler to be replaced because he didn't play a domestic match but he ends up playing the next ODI.
Thats what I think about it, even for tests too. Only injured players should be replaced.