After three successful seasons of "Fargo," it is still uncertain when the fourth one is coming out on the horizon because of showrunner Noah Hawley's packed schedule.

FX CEO John Landgraf told reporters at the Television Critics Association summer press tour in Los Angeles this week that studio heads haven't heard from Hawley on what he plans to do for "Fargo" in season 4.

He said, "What we've encouraged Noah to do is think about it and make sure he has an idea he's excited about."

Hawley is currently busy with a number of projects which include the second season of FX series "Legion," which is based on the "X-Men" franchise, and an upcoming movie based on the Marvel villain Dr. Doom.

The first season of "Legion" recently concluded and was well-received by critics. It told the story of David Haller (Dan Stevens), a mental patient who was later revealed to have powerful psychic abilities.

Aside from "Legion," Hawley is also developing a "Dr. Doom" movie for 20th Century Fox. At the "Legion" panel during San Diego Comic-Con in July. he revealed to the audience, "I'll just say two words. The first one is Doctor and the next one is Doom."

Landgraf acknowledged that Hawley is going to be considerably busy with these projects and that his idea for the new season of "Fargo" won't come after some time.

"We're going to have to share him with our film studio and we're going to have to figure out how to make that work," the executive expressed.

Hawley said in June that season 3 of "Fargo" is not necessarily the end.

"Right now, I just can't point to (a production start) date on the calendar. I always agreed with FX that the only reason to do another Fargo is if the creative is there," he explained.

Given Hawley's current schedule, "Fargo" season 4 is expected to arrive sometime in 2019.