Bad idea.
I don't think our players should have periods, as they would blame their bad games on them, and not show up to practice because they had an aunt in town.
Oh, and they would be miserable to be around for a week before that, and no fun during that week. Imagine buying a guy off the transfer list, trying to plug him into your line-up and finding out it was his period. Oh, and what if all your players started to get on the same cycle!? Your whole team could be a mess for a week, and that wouldn't be fun for anyone.