Australian rock trio Silverchair has pushed back the North American release date of its Atlantic Records debut "Diorama" to Aug. 27.

Australian rock trio Silverchair has pushed back the North American release date of its Atlantic Records debut "Diorama" to Aug. 27. The album was originally slated to be released July 9, 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.

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.

Its original promotional tour plans scrapped, the group is actively trying to promote "Diorama" through the Internet with multiple live chat sessions and a deal with the MSN network that will offer a few streaming exclusive live tracks in August. The group's official Web site is hosting a multimedia exhibit on the making of "Diorama" and other updated features.

The album, Silverchair's fourth and first in three years, debuted in April at No. 1 in Australia. Featuring production by David Bottrill (Tool, Peter Gabriel, King Crimson) and arrangements by Van Dyke Parks, the album is the follow-up to 1999's "Neon Ballroom" (Epic), which has sold more than 520,000 units in the U.S., according to SoundScan. That album spawned the top-15 rock airplay singles "Anthem for the Year 2000" and "Ana's Song (Open Fire."