The heavy rockers have refused to identify Joey Jordison's replacement in the band, but it has been widely reported the new drummer is Jay Weinberg, the son of longtime Bruce Springsteen sidekick Max Weinberg.
And now Grace appears to have confirmed the news in a tirade about her former bandmate, who quit Against Me! in late 2012.
In a tweet on Thursday (18Sep14), she wrote, "Dear Slipknot, good luck with that. #s**tbag."
Grace previously recalled the drummer's departure, insisting she still has no idea why he quit.
She said, "I woke up one morning and read on Twitter that he was leaving. I have never talked to him since."