Corey Taylor, frontman of Slipknot and Stone Sour has announced that he is set to undergo surgery on both of his knees today, May 10th. He shared the below pre-op picture from the hospital via his popular Instagram account. Hopefully, the injury doesn’t sideline him too long as Slipknot if completing their new album due out August 9th , and the band is set to appear on Jimmy Kimmel Live! next Friday, May 17th.