Major, major bummer. Opeth has been he and Mike's life for the past 16 or so years and the one time I've seen them live, he was awesome. According to the news on Opeth.com, the long months of touring took its toll and his enthusiasm- being able to put in 100% to the band was something he felt he didn't have in him anymore. They announced a replacement already. Guy's name is Akesson and apparently he subbed for Arch Enemy once. Mike rates him as one of the top 3 guitarists in Sweden. Best wishes to Peter! Hope the band continues going strong.