The Hodgkin's lymphoma that Def Leppard guitarist Vivian Campbell has been battling for two years has returned. This rough news comes on the eve of his band's tour, and his announcement indicates he will be sidelined for an undisclosed period of time.

"I'm saddened by the fact that my cancer has returned," he wrote on his Facebook page. "However, I'm beyond consolation that it's return will prevent me from being able to do my job for a while. I’m still working on a schedule of treatment with my doctors, but I will see you all very soon. My apologies." (Ultimate Classic Rock reached out to Def Leppard's publicists and were told that no further statement from the band will be issued at this time.)

Campbell was diagnosed with Hodgkin's lymphoma in June 2013. By November, he had received word that it had gone into remission. But it returned last September, which caused him to undergo a stem cell transplant. Since then, all updates about his health had appeared positive – in fact, as recently as April, Campbell admitted that he had come to enjoy having short hair for the first time in his adult life.

On Tuesday, Def Leppard will begin a three-and-a-half month tour with Styx and Tesla. The band has not yet announced his temporary replacement. When Campbell had his stem cell transplant, Trixter guitarist Steve Brown filled in for him. Brave Words is reporting that Brown is rumored to take his spot again, saying that he had posted the dates on his website, but also that they have since been removed.

See Def Leppard and Other Rockers in the Top 100 Albums of the '80s

You Think You Know Def Leppard?