The "Piano Man" has been hobbling around with a cane due to a congenital hip ailment in recent weeks, and relied on the cane when he celebrated the grand opening of his motorcycle showroom, 20th Century Cycles, in Oyster Bay, Long Island earlier this month.
When he stopped by Howard Stern's studio to do an interview last week, he was noticeably weak, according to E!.
"He looked so frail, he was struggling to get around, to walk it looked like," a source who saw Joel on Nov. 16 tells the website. "He had crutches and was moving slowly, kind of dragging them on the ground and grunting. People with him were being very patient, and he was nice and seemed in a good mood, just moving pretty slow."