Back when it was first announced that Thor 3 would be titled Thor: Ragnarok, fans became interested as to how closely it would follow the comic stories that it could be based on. Then, when it was revealed that the movie would be a team up between Thor and Hulk, speculation began to point towards the film having an influence from the Planet Hulk storyline in the comics. This idea became even more clear when Hulk's gladiator armor was shown at San Diego Comic-Con, but that has not been the only information pointing towards the idea of the story being implemented.
Director Taika Waititi has already teased the appearance of Korg and confirmed that of Meik, both of whom have roles in the storyline. Now, he has confirmed the largest connection yet by revealing that the war planet of Sakaar will be featured as well.
The information comes courtesy of an interview with Total Film that was posted by a Twitter user (via MCUExchange) where Waititi confirmed that this is where Hulk and Thor will be reunited. His quote from the article is as follows:
Sakaar was just an insane, far-off futuristic place which was the biggest shift for the film and these characters.
Now that it has been confirmed that Sakaar will be a major piece to the film's story, it continues to show how much inspiration is being drawn from the Planet Hulk story. The article points to Hulk presumably having been a warrior on the planet for some time which makes sense as Hulk was last seen flying away in the quinjet at the end of Avengers: Age of Ultron. Should he have crashed on Sakaar shortly after, he would have years to fight in the gladiator matches and build up his reputation.
Sakaar is more than likely also the base of operation for Jeff Goldblum's The Grandmaster, where he will then pit Hulk against Thor upon his capture as well. No matter how that battle plays out, the former Avengers should not be fighting against each other for long before teaming up to escape. This is also where Tessa Thompson's Valkyrie is said to be involved as well, but that has not been confirmed as of right now.
Should Grandmaster be ruling Sakaar, it will be a departure from the comic story, but as they have already appeared to have borrowed a number of elements, changing this should be to the benefit of the story. It should be interesting to see how heavily shown the actual Sakaaran race is in the film after previously being members of Ronan's Kree army in Guardians of the Galaxy. If they do have a presence, they will once again find themselves under the command of another blue-faced ruler, but maybe Thor and Hulk will help overthrow him in their escape.