Which R.E.M. drummer left the band in 1997?

Bill Berry was the R.E.M. drummer who left the band in 1997. He had been part of the original four-member lineup with Michael Stipe, Peter Buck, and Mike Mills since the band's formation in 1980.

Berry announced his departure in October 1997 after deciding he no longer wanted the demands of life as a touring rock musician. His decision followed a serious health crisis: he suffered a brain aneurysm during a 1995 concert in Switzerland and later recovered. Berry told his bandmates he would remain if they chose to break up, but Stipe, Buck, and Mills decided to continue as a three-piece.

R.E.M. carried on without a permanent replacement drummer, using session and touring musicians when needed. The other choices were the band's vocalist, guitarist, and bassist respectively, so none of them fits the question.