User blog comment:Omega natsu2/Chapter 362: Natsu vs. Jackal, Predictions./@comment-76.124.155.27-20131122163154/@comment-7418318-20131124080907

Pyxis was more of a joke. I don't think Mashima would just randomly let a serious silver key pop up out of nowhere.

Besides, Lucy has too many combat oriented gold keys for it to make sense for her to use silver keys, unless it's as a last resort at a point where she is too exhausted to summon another Zodiac.

But I wonder if maybe we'll see some silver keys in action from Yukino or Angel turning up (not in this particular fight, but later in the arc).