Pentatonix Losses a Member

Avi Kaplan will be leaving Pentatonix. Avi announced his departure Friday morning in video posted on the group's Facebook page. 

Avi says he'd been struggling to keep up with the fast pace of the band, and missed his friends and family as well as not being able "to escape into nature when I’m feeling overwhelmed or just need some time to myself."

Pentatonix won the third season of NBC's "The Sing-Off" ... and they pop up on almost every award show doing tribute performances. They're about to kick off a summer tour that includes gigs in Japan, and 3 nights at the Hollywood Bowl.

Avi says he'll still do all those shows, but after the tour he is leaving the group.

The other members did NOT seem thrilled during his taped announcement.