It would be different if there were a starting goaltender and backup goaltender. I think it's fair to Danny to give him equal playing time. If one of them is clearly stealing the show, ride him. Otherwise, I'm not sure this is being done to 'fix' things as much as it just a fact that we have two legit AHL starters on this team.
You justify it because Sabourin earned it with his play this season. One or two games, especially when the team isn't scoring, probably isn't going to make or break the development of Fleury. He's down there to try to be part of a playoff run and play in some important games, but that doesn't mean he has to play every game.