Ask on Wikianswers Anime

Well, the recent episodes about the Straw Hat's nakama's whereabouts in the Manga appear as Cover Story, whereas in the Anime they needed more time to talk about every single member. Als, they might be having a hard time preparing all, because the Marineford Battle is one of the most spectacular and complicated arcs in the One Piece world, given the enormous number of its partecipants and the fights taking place.

the anime can not catch up to the manga that is why filler is added and the reason toei is putting off marineford. When a manga has an anime adaption the anime must never catch up to its coutnerpart because that causes problems. it takes at least two weeks and more then one chapter to make a single episode of one piece that mean a new episode wouldnt come out for at least 3 weeks if it caught up. so instead toei adds filler to give oda enough time to come out with new material. Some anime even go as far as putting shows on hiatus till enough chapter can come out to solve the problem of the possibility of catching up