Atlanta progressive metallers MASTODON have cancelled their previously announced summer tour, which scheduled to launch in Germany on June 5 and be completed in Finland on July 3. The band's guitarist, Bill Kelleher, was diagnosed with pancreatitis (a sudden inflammation of the pancreas which can have severe complications and high mortality despite treatment) and was advised by doctors to pursue further medication. Doctors are optimistic and expect a full recovery in the coming weeks for Bill, as the band is eager to take part in the BlackDiamondSkye tour, along with ALICE IN CHAINS and DEFTONES, scheduled to open in Chicago on September 16.