LOS ANGELES, Aug. 11 (UPI) -- U.S. rock band Sum 41 says it has canceled several dates on its Vans Warped Tour because lead singer Deryck Whibley is hurting after being attacked in Japan.
Sum 41, in a posting on its Web site Tuesday, said the band had expected to resume playing on the tour this week after having taken a break to play Summer Sonic festival dates in Japan.
"Unfortunately," the band said, "... Whibley was attacked in a random unprovoked incident in Japan last Thursday night, which aggravated a previous slipped disk injury that he sustained in 2007. After seeking medical attention, Deryck and band mates Steve Jocz, Cone McCaslin and Tom Thacker went on to play as part of the festival in Osaka and Tokyo."
Although the group went on to say Whibley's condition has not improved, the musicians also said he is expected to make a full recovery with treatment and rest.
"Being a part of the Warped Tour this summer meant a lot to us. We haven't toured in two years and the bands, the crowds and the entire Warped Tour crew have been amazing to us," drummer Jocz said in a statement. "We were excited to be back in front of our fans and are very disappointed that we have to pull off the tour. 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."
The band said it will be back out on the road again in Europe at the end of August.
The group previously played more than 20 Warp Tour dates this summer across the United States and Canada.
The assault on Whibley is still under investigation in Japan.