User blog comment:IamJakuhoRaikoben/Chapter 291: Naval Battle, Review./@comment-32.129.29.43-20120713130046/@comment-3290324-20120713130242

No, because Minerva is too strong to be attacked by Libra and she would likely have just sent Pisces out with her Magic. Furthermore, summoning Pisces would probably knock Lucy out as well. And, Juvia can turn her body into water so I doubt Libra could make her drop out and Pisces couldn't knock her out because Juvia can't be touched by physical attacks.