Jazz keyboardist Herbie Hancock has canceled his September 20 concert at the Nob Hill Masonic Center in San Francisco, CA, due "to unforeseen circumstances," according to a statement released by concert promoter Live Nation.

Ticket refunds are available at point of purchase for the canceled show. However, Hancock's performance at the Mountain Winery in Saratoga, CA, on September 19 is still on the books, and Live Nation will offer Masonic ticket holders a discount for Hancock's performance at the Mountain Winery. Hancock's performance at the Monterey Jazz Festival in Monterey, CA, on September 21 is also still a go.

These shows, which conclude the musician's 2008 tour dates, feature Vinnie Colaiuta, Nathan East, Lionel Loueke and Amy Keys in Hancock's backing band.

On the 2009 itinerary, Hancock is scheduled to play the Playboy Jazz Cruise At Sea sailing on January 21. Earlier this year, Hancock performed at the 30th annual Playboy Jazz Festival at the Hollywood Bowl.