(Cover) - EN Showbiz - Sum 41 have been forced to take a break from touring so Deryck Whibley can recover following his attack.

The singer was reportedly beaten up by three people in a bar last week while the band were in Japan. After the attack he was taken to a local hospital and treated by medical staff. An MRI scan showed he had aggravated a previous disc injury in his back and the band have now decided Deryck – the ex-husband of Avril Lavigne - needs some time to heal.

"Knowing that they are unable to deliver their signature high energy show, Sum 41 made the tough decision that a break is needed while Deryck begins rehabilitation for the slipped disc," the group said in a statement on Wednesday.

The rockers also revealed 30-year-old Deryck’s condition hasn’t improved since the attack, but insist he is expected to “make a full recovery with the necessary treatment and rest".

The band were due to play dates in California, Washington, Idaho and Oregon on their Vans Warped Tour this month.

"[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," drummer Steve Jocz said. "Deryck is doing everything he can to get himself better and we're there for him."

Sum 41 are hoping to return to the stage at the end of August to play a series of dates in Europe. (C) Cover Media