Australia's SILVERCHAIR have pushed back the North American release date of their Atlantic Records debut, Diorama, to August 27th. The album was originally slated to be released on July 9th, but singer/guitarist Daniel Johns' battle with reactive arthritis — which is preventing him from participating in promotional activities — forced the label to make the move. The extra time will be used to generate additional TV and radio airplay to help the album make a bigger splash went it eventually hits the shops. Release dates in other countries remain unchanged.As previously reported, the group has had to cancel a number of shows in its homeland as a result of John's illness, the primary symptoms of which are chronic swelling of the joints resulting in impaired movement and extreme pain. Johns is currently recovering, according to a statement from Atlantic.