The five rings thing is fun to think/talk about, and if she gets it, fantastic! But I think that would be about the worst possible reason to come back for a fifth year.
Tenspro and GG have illustrated the conundrum she faces, the two sides to the knee problem. Given the bad knee, do you go for insurance and come back for a fifth year and work on a master's? Or do you look at as though you have to make your money while you can, so you go pro. Some would say it's a risk to come back and maybe suffer another debilitating injury, so go pro. On the other hand, if she passed on the free schooling, went pro and got hurt right away, she could possibly lose both.
Doris mentioned that Morgan and Geno had had some frank discussions. I hope he can advise well on what her chances of success are. Most of what we think of as her strengths are on the offensive end, and mostly under the basket. She is probably going to be much less effective down low at the pro level. Yes, she has a long range shot in her arsenal, and she's a good passer. Her rebounding seems only so-so, as well as her defense.
So I don't know. Of course I hope she will come back, but if she goes I sure hope it works out.