Neil partially tore the medial portion of his calf muscle five songs into Crue's concert Saturday night at Phillips Arena, the band said in a news release.
"I just felt something snap in my leg, like a cramp," Neil said in the release. "I just couldn't go on."
Although doctors urged Neil to take time off, he announced: "I am a trooper," and vowed to take the stage as scheduled Sunday night in Memphis.
The band said it would return to Atlanta and honor all tickets from Saturday night's aborted show.