Founding member of AC/DC Malcolm Young has officially left the band, the group announced today. The band cited the guitarist’s stroke in April as the reason he will not be returning to the band. Young’s nephew Stephen will accompany the band on their upcoming 2015 world tour.

AC/DC also confirmed a new album, Rock or Bust, due out December 2. The lead single, “Play Ball” will serve as the soundtrack to Major League Baseball’s postseason games beginning in October.