Sum 41 has pulled out of their spot on the Vans Warped Tour as frontman Deryck Whibley remains in an Asian hospital recovering from injuries he sustained in an attack last week.

Sum 41 was in Japan to perform at the Summer Sonic Festival when Whibley — who is the former husband of pop singer Avril Lavigne — was assaulted by three men in a local bar last week. He suffered a slipped disc in his back and is expected to recover, but the culprits remain at large.

In a statement on Wednesday, the band said their decision came after realizing they would be “unable to deliver their signature high energy show.”

“[We] are very disappointed that we have to pull off the tour. [But] we know that it would be more frustrating for the fans if we can’t give it our all. Deryck is doing everything he can to get himself better and we’re there for him,” drummer Steve Jocz explained.