I have read a lot of good things here on this topic. I coach at a relatively small school, so I have never really had this problem. I am going to have a few seniors this year who probably may not see the field very much- two girls who have started in the past, but didn't play last year due to injuries, and my returning DP. I am going to talk to them and let them know where they are. In fact, I already talked to one. I wanted to give her a chance to save face by "deciding" not to come out this year on her own, rather than come to the games and be upset on the bench. Another one may present an attitude problem if she doesn't start (and she won't), so she will get the speech that as long she doesn't complain and is willing to support the team that she is welcome.
Many seniors do not like sitting. If they are told the truth up front many will choose not to play. Granted, it is pretty tough sometimes if you don't follow the players in the off-season to do this ahead of time, but as soon as whatever tryouts you have are over, honesty is the best policy.
The best players have to play. What must be found out though is who can handle the pressure. Two years ago a freshman looked like a lock for shortstop prior to the first game, but after 6 games or so, it became obvious that she wan't ready for varsity competition. Many teams have girls coming out with a lot of travel experience, which negates this issue, but I unfortunately do not.
While parents look at what is best for their daughters, coaches should be looking at what is best for their program. I absolutely hate when a player or parent tells me she should play because of what grade she is in. The only time what grade someone is in truly matters is when I submit my eligiblity form. I do not believe in playing a senior on a JV team unless it is a numbers problem. So again they need to be aware of this. Looking at the numbers provided, I would certainly try to have two JV teams if the talent warrants it. It depends on where the freshmen will play and contribute, and if you can find enough games for 2 JV teams.