The online rumors started after fans noticed that the former Queens of the Stone Age drummer did not perform with the band at a show in Lawrence, Kansas on Tuesday night.
Weiland posted a message to fans to explain that Castillo has only stepped away from the band temporarily and Mike Avenaim, who played on several tracks and co-wrote one song on the band's debut "Blaster", would be filling in.
Weiland wrote, "Just to clear up the confusion - Joey has NOT left the band. He is recording for a week with BL'AST and will meet back up with us on the 27th. I've known about this for months, hence lining up our friend Mike Avaneim [sic] to fill in." -