The band was about five songs into the concert Friday night when Neil leaned over to sing along with the audience and slipped off stage, said police spokeswoman Sylvia Abernathy.
"I just felt something snap in my leg," Neil wrote on the band's Web site. "I just couldn't go on."
The band was forced to end the concert early. Neil was treated at Piedmont Hospital (search) and released Saturday, hospital spokeswoman Diana Lewis said.
The band said on its Web site that Neil partially tore part of his calf muscle. He planned to perform on Sunday night in Memphis, Tenn., and no shows were being canceled, the band said on its Web site.
The 1980's glam band recently reunited after six years apart. Band members said they intended to return to Atlanta for a makeup show.