Polish blackened death metallers Behemoth have regretfully had to bow out of this summer's Rockstar Energy Drink Mayhem Festival, which kicks off June 29.

The band is bailing because drummer Inferno has fallen ill and required appendix surgery. He will be unable to smash the skins during the recovery process, so rather than recruit a fill-in, the group has decided to cancel its appearance on the annual summer trek. For the band, anything less than a full-strength Behemoth is unacceptable.

Frontman Nergal addressed the group's exit from the tour, saying, "This must have been the most difficult decision we were forced to make in recent years. Behemoth is known for not canceling any shows or tours. But this is not something we can do when we are missing our driving force, the man behind the drums -- Inferno."

Nergal continued, "Unfortunately, he was hospitalized due to appendix surgery and it's gonna take him few months to fully recover and get back to shape. We are trying to save selected European Festivals with a fill in drummer (Krimh, ex-Decapitated), but we won't be risking doing a full-on prestigious tour like the Rockstar Energy Drink Mayhem Festival without Inferno. Behemoth is a solid unit and any part of this unit missing makes us weaker, and that is not how we want to present our new material to our fans. Please, accept our apologies and be patient, we shall return to Europe (this fall) and US (early 2014) empowered and motivated as never before!"

Behemoth are no strangers to a debilitating illness getting in the way of their tour plans. Nergal was diagnosed with leukemia in 2010, and the band understandably had to cancel a tour as a result.

While headbangers will no doubt miss the band on the tour, Noisecreep sends our best out to Inferno as he recovers. Behemoth will release 'The Satanist' this fall. So while we won't see 'em on the road, that's indeed something to anticipate.