Black Sabbath posted video of recording 13 in the studio with Brad Wilk of Rage Against the Machine. The band had two weeks before recording to practice and get a feel for Wilk. BS admitted that the first week was a disaster. They panicked and thought they hired the wrong guy, who was suggested by Producer Rick Rubin. But, Rubin worked with Wilk and got him where Black Sabbath wanted him.
Ozzy just let it slip that he wasn't happy with how the replacement drummers search was handed. Tommy Clefetos is the drummer in Ozzy's solo band, and was kept on hold by management, even though Rick Rubin did not want Clefetos on the album. (He wanted Ginger Baker or Brad Wilk, even though Clefetos would go on tour with Black Sabbath). Ozzy thought it was wrong to keep someone on hold when they won't get the gig. That's time Clefetos could have been working with another band.