The news was first reported at ShowBiz411.com.
Clemons is 69, AP says. Rolling Stone reminds us that he "has gone through a series of medical ailments — mostly involving his back and knees — over the past decade."
As ShowBiz411 says, "it's [Clemons'] trademark sound on Rosalita and other songs from The Wild, the Innocent and the E Street Shuffle that established Bruce, and moved him from singer songwriter to R&B aficionado."
So far, none of the news outlets have many details about Clemons' condition.