The storyline for The CW's "Arrow" has had fans at the edge of their seats. After all, Oliver Queen had to fight a lot of bad guys over the course of the last three seasons, and among them are the more iconic ones like Deadshot and Slade.

However, it seems that there's one villain that everyone has been looking forward to who has to take the back seat, despite having already appeared in a promo video and providing her voice in the show's second season, things that MTV News has noted for fans.

Yes, Harley Quinn was supposed to antagonize Ollie and the gang, but it seems that plans have changed, especially considering that she's taking center stage on the upcoming "Suicide Squad" film.

When Harley's appearance became an issue back in season 2, producer Mark Guggenheim said to Collider, "I want to manage expectations with respect to Harley Quinn. She was always intended to be an Easter egg. I don't want people to go in with incorrect expectations and walk away from Episode 16 disappointed."

However, it seems that Harley was really supposed to have a big storyline in Starling City. Willa Holland (Thea Queen) mentioned that Joker's lover is supposed to have a bigger role in "Arrow" before the "Suicide Squad" movie was announced. She told reporters present during MCM London Comic Con (via Flickering Myth), "We had big plans for Harley. But, I guess something came down from DC execs that told us to shut it down. I mean we had that tease with the pigtails and the A.R.G.U.S. outfit, but we'll never see it. We would love to [have] Harley in 'Arrow' but it will never happen."

The International Business Times mentioned that the upcoming "Suicide Squad" film, which is going to be a full-on supervillain team-up, has played a significant role in ensuring that several characters, including fan-favorite Harley Quinn, won't appear in the series.

As mentioned by website Comic Book Movie, casting Margot Robbie in the film means that Harley and Task Force X "will be off limits for The CW."

It may be due to planning but the deal did not stop "Arrow" from having Deadshot in the series as well as Tatsu Yamashiro AKA Katana, who had a major role in the last season. However, Deadshot has already been killed off in "Suicidal Tendencies" and Rila Fukushima, who played Tatsu, has not been confirmed to return next season.

What do you think of not having Harley in "Arrow" even though we already caught glimpses of her? Are you one of the many who hoped to see her fight with Ollie? Check out the deleted scene from season 2: