One song into their Springfield Summer Concerts Series performance Thursday night, Grantham collapsed and was taken to Bay State Hospital. While Grantham -- a founding member of the band -- was undergoing surgery, the rest of the band played the rest of the show acoustically.

Rick Alter, a spokesman for Poco, said doctors are optimistic that Grantham will make a full recovery, but it is not known whether he will drum again. Alter said Poco would play a scheduled date Friday in Cape Cod without a drummer, and then go from there with George Lawrence, a drummer who worked with them in the mid '90s.

One of the leading bands of the Southern California country-rock movement that included Jackson Browne, The Eagles and Linda Ronstadt, Poco had just completed taping a reunion concert at Nashville's Belcourt Theatre for an upcoming DVD release.