West, 65, underwent the emergency surgery after being admitted to a hospital in Biloxi, Mississippi, on Saturday when his leg started to swell and his foot went septic.

"The doctors tried for two days to save it to no avail. The decision to amputate was one that was necessary to save his life as the infection was spreading throughout his body," his wife, Jenni West, said in an email.

"The nursing staff and doctors have taken excellent care of him and should be called angels for their efforts and tenderness they showed us in this time of crisis."

West is expected to recover but faces extensive rehabilitation, a spokesman said.

Mountain is probably best known for its debut 1970 single "Mississippi Queen," a staple of classic rock radio. West has long struggled with his weight and type 2 diabetes. He named one of his solo albums "The Great Fatsby."

His next album, "The Unusual Suspects," featuring such guitarists as Billy Gibbons of ZZ Top, Slash of Guns N' Roses and Joe Bonamassa, does not yet have a release date.

"Leslie will, no doubt, bounce back with his unusually bionic blitz of guitarosciousness," Gibbons said in an email. "Leslie will always be playing and standing on higher ground."