UPDATE: Starz has decided to recast the lead role.

Andy Whitfield’s long-anticipated return to Spartacus: Blood and Sand has been canceled altogether.

The actor, who was diagnosed back in March with non-Hodgkin lymphoma, had already been training for Season 2 of the Starz series. Although he was given a clean bill of health back in June, a recurrence of cancer will now require “aggressive treatment.”

“It’s with a deep sense of disappointment that I must step aside from such an exceptional project as Spartacus‚ and all the wonderful people involved,” Whitfield, who played the title character, said in a statement. “It seems that it is time for myself and my family to embark on another extraordinary journey. Thank you sincerely for the support so far.”

Starz had originally hoped Blood and Sand could return to the schedule sometime around September 2011. Now it’s unclear what the series’ future may hold. “Right now, we just want to extend our concern and support to Andy and his family,” said Carmi Zlotnik, the Managing Director for Starz Media said. “We will address our programming plans at some later date.”

In the meantime, Spartacus: Gods of the Arena, a prequel that was conceived during Whitfield’s original absence, will air as scheduled. That chapter—featuring John Hannah (Batiatus) and Lucy Lawless (Lucretia)—debuts in January.