A statement taken from the bands website explains:

To our Maggots and fans around the world,

It is with great pain but quiet respect, that for personal reasons Joey Jordison and Slipknot are parting ways. We all wish Joey the best in whatever his future holds. We understand that many of you will want to know how and why this has come to be, and we will do our best to respond to these questions in the near future. It is our love for all of you, as well as for the music we create, that spurs us to continue on and move forward with our plans for releasing new material in the next year. We hope that all of you will come to understand this, and we appreciate your continued support while we plan the next phase of the future of Slipknot.

Thank you,
The 'Knot"

With one of the founding members Joey leaving the scene, it’s hard to say who will follow in his footsteps and emerge as the next drummer of slipknot but it’s definitely a sad, sad day for maggots.