Rod Stewart postponed his Aug. 9 concert in Cincinnati, Ohio, two hours before doors were set to open. Organizers shared a brief statement online telling fans that “due to an unforeseen but minor medical procedure that required prompt attention” his performance was postponed. The statement also noted that “Rod is expected to make a quick recovery,” and stopped short of disclosing what sort of medical procedure he underwent. Stewart was scheduled to perform as part of the “One Last Time” North American tour. (RELATED: Rod Stewart Deeply Inhaled From Oxygen Tank Amid Onstage Health Scare)The famous singer has shown signs of ailing health in recent weeks.