User blog comment:FairyRaven/Fairy Tail Chapter 425: Sabertooth X792, Review and Commentary/@comment-76.121.234.236-20150324105814/@comment-26239138-20150325223315

No, he trained for many reasons and that is including the thing about Frosch. He didn't train for Frosch alone, he's just one of the reasons.

They went after Wendy first because she's in a nearby town. They have no idea where Gray is so they go to Juvia next. They are gathering info.