There are summer leagues now in Florida (and probably other places) specifically designed for college players. In some cases college coaches recommend a player play in summer to get reps and in some cases they might recommend a player not play. I would suggest any interested player discuss it with her coach. The most logical candidates would be players who didn't feel they got the reps they needed during the season, or are maybe coming off injury, and are looking towards a bigger role in the coming season. I have had several players in recent years elect to do it or have it suggested to them by their coaches. If you played a ton during the current season it would make less sense to me, but to each their own.