The band didn't provide a reason for Duce's exit, but had this to say, "The split is amicable, and Machine Head would like to wish Adam the best with his current and future endeavors.

"The band will continue on for the time being as a three-piece and have begun the writing process for their follow-up to 2011's 'Unto The Locust'. A late 2013 release is projected."

Duce cofounded the band with Robb Flynn in 1991. Last year Duce gave an interview to the Dutch publication FaceCulture where he disclosed some dissatisfaction with the band and his level of involvement, according to this report.

"I had some issues with [the writing] process [for 'Unto The Locust']. I kind of took myself out of it until it was time to write my bass lines. I wrote a bunch of music, or riffs, that Robb [Flynn, guitar/vocals] didn't have any idea what to do with vocally, and so he didn't wanna use any of that. But more importantly, I wrote lyrics that meant a lot to me and I gave it to him. I've given him page after page after page of lyrics. And it usually comes back that way, [where] he'll use a verse or a part of it or whatever — 'I'm gonna take this part and put it down here.' . . . whatever works for the cadence. But I got kind of burned on putting my soul out on a piece of paper and giving it to him and when I see it next time, there's no remnants of what the original idea was. And I was just like, 'You know what, dude?! I'm not giving you any more f**king lyrics, because I'm f**king sick of looking at this, the way that it f**king turns out.' I said, 'I'll work on it with you at the same time, but I'm not giving you any more lyrics. I'm not giving you pages of lyrics.' He was f**king angry at me for a while, but you know… that's f**king what happens."