A sixth installment to the worldwide hit "Grand Theft Auto" is once again strong in the rumor mill. Could a sequel be really out in 2021?

GTA fans believe, or at least just strongly hope, that 2018 is the year Rockstar Games announces a "GTA VI," particularly at the upcoming E3 in Los Angeles in June.

However, gaming industry specialist Michael Pachter believes Rockstar would not be announcing a GTA expansion until 2020, for a 2021 release. That is already the best case scenario. He explained the year in between as Rockstar's normal pace, wherein it announces their games a year earlier.

In an interview with Gaming Bolt before the 2017 year-end, Pachter based the time frame on the game developer's recent boost for "Red Dead Redemption 2," which many believe will hit the stores come spring this year.

"It'll take over/under in 2022," Pachter said about the possible "GTA VI" release date. "Remember, 'Red Dead Redemption 2' comes out eight years after the first one -- so the idea that 'GTA 6' comes out before 2021 seems ridiculous." Realistically speaking, the expert said there is a better chance for the much-awaited sequel to come out beyond 2022.

While gamers still have a long wait ahead, Gaming Bolt explains that all these are already a very positive estimate. The "Grand Theft Auto" franchise, which started in 1997, has always had a long wait in between installments.

Now with Rockstar divided between two huge franchises -- "GTA" and "Red Dead Redemption" -- the company must be running thin with manpower and resources.

It has been over four years since "GTA V" was released to the marker, yet it remains widely popular among fans, thanks to its timely downloadable contents that keep the excitement alive.

Even now, the widely popular game, which is currently available on PlayStation, Xbox and PC, is reportedly slated to bring its sweet ride to Nintendo Switch.