NEW YORK – The NFL revealed Sunday that several positive COVID-19 tests were found a day earlier by one of its testing partners, and the Chicago Bears said they had nine false positives.The league has asked the New Jersey lab BioReference to investigate the results “while the clubs work to confirm or rule out the positive tests.” The NFL did not identify the teams or say how many tests were positive.Two teams, Washington and Detroit, said they are practicing Sunday, while Cleveland has called off its workout.The NFL uses BioReference for all of its COVID-19 testing, though tests are handled by labs throughout the nation to ensure teams get results quickly — hopefully within 24 hours.