Kerrang is reporting that the recording of Green Day's next album has been postponed. Drummer Tre Cool recently had surgery on his knee and has been told by doctors to stay off his feet. In an audio message on the band's website Cool stated: "Hey everybody. This is Tre. I've got a big, huge piece of bone here in a jar and I'm gonna give this little motherfucker away to one of you guys. It's gonna be yours! A piece of my leg. A piece of the inside of me. I don't know how I'm gonna pull it off yet but y'all have to wait."