Wentz writes in an online post that, "I wanted to apologize to people who came out to the last couple warm-up shows — I have done something to my back that makes it hurt for me to even walk." In a separate post, he added, "I did something to my back while doing a stunt for the video. I think it will all be worth it when the video comes out in the end. I hope it is something you're gonna love. No shows will be canceled, but like I said, I feel terrible when I don't feel like I am able to give absolutely everything I have on the stage. You know what they say, 'No pain, no gain,' and all."

The video for FOB's new song, "This Ain't A Scene, It's An Arms Race," debuts on MTV this Tuesday, December 19. Bob McLynn, a spokesperson for the band's management, told MTV.com that Wentz did injure his back and has been "playing in pain for about two weeks now and he needs to get another checkup." He continued, "He hasn't been able to rest ... and that's the problem. He has swelling in the middle of his back, and he still needs to get it checked out, but he's committed to doing as many dates as possible. He was supposed to have it checked out in Los Angeles, but he had to go play KROQ's [Almost Acoustic Christmas], then fly out to Seattle, so he didn't get to have it looked at by a doctor. Even when the band has days off, like they did in Minneapolis the other day, they're still out doing things for the record."

Fall Out Boy won't have much downtime in the near future, as they are set to begin their Friends Or Enemies tour in San Francisco on January 4.