The show's second season was delayed after Whitfield was diagnosed with non-Hodgkin lymphoma.
Starz later confirmed that it will make a prequel series, which will feature Whitfield in two episodes.
"I'm raring to go," Whitfield told Deadline.
He added: "After the initial shock [of the cancer diagnosis] - I was a healthy young man and had no idea this could happen - it was frustrating that the first season was ending on such a high note and we could've been rolling into season two."
However, Whitfield explained that he has had "time to heal, figure things out and spend time with my family" and said that he has learned to "stay in the now and enjoy every moment".