is one piece episode 872 filler?

A man stationed on one of the Big Mom Pirates' ships surrounding Cacao Island sees the Thousand Sunny approaching, and shouts the news to his crewmates around him. The Sunny crew marvels at the massive force gathered on Cacao Island as they continue to be pursued by Smoothie's fleet, which intends on using the fleet around Cacao Island to trap the Sunny.

On the island, Oven's army is on high alert for Luffy to emerge from the mirror in front of them, and Sanji impatiently waits for Luffy.