Blues Traveler singer/harmonica player John Popper was released from Los Angeles' Cedars-Sinai Medical Center on Saturday following surgery to clear a blocked artery in his heart. The 32-year-old Popper had been experiencing chest pains for three months and was admitted to the hospital July 1 for testing that led to the discovery of the blockage. According to a press release, "all public appearances through the end of the month have been postponed" — including the live debut of the John Popper Band, initially scheduled for July 16 in Chicago. That show has been pushed back until after the group's debut, Zygote, is released Sept. 7. A spokesperson at the band's label said the group plans to begin work on a follow-up to 1997's Straight on Till Morning by the end of the year.