George Jones was admitted Thursday (April 18) to a Nashville hospital for observation. During a routine checkup, the 81-year-old singer was running a slight fever with irregular blood pressure, his publicist stated. He has canceled concerts Friday in Atlanta and Saturday in Salem, Va. Both shows are expected to be rescheduled. According to his website, his next tour date will take place April 27 in Huntsville, Ala. Jones plans to perform his final concert on Nov. 22 at Nashville's Bridgestone Arena.