User blog comment:Besteverunited/Do you think after the tartarus arc there will be a break in the anime or is the new manga arc designed for this reason?/@comment-4933386-20150225104302/@comment-7418318-20150226074346

Natsu vs. Mavis is very short and would barely make a third of an episode by itself and I seriously doubt we'll be seeing any crossover Omakes in the actual anime.

The Penalty Game is connected directly to the GMG thus I think it would already have been done if they were going to do it as an episode. But with the stuff between Erza and Mirajane and some of Wendy's outfits this one's better suited for an OVA anyway.