It is good to get guys like Pierce and Ray playing time with players that they usually don't play with for that long on the court. The best way to get timing down is to play with them, obviously.
Doc most likely wanted to get Ray playing time with Daniels, House, Sheed, and Williams. How can a player be comfortable in a game if he isnt used to how his teammates play around him? We also know that Doc likes to experiment with lineups.
To me, not an issue.