NFL: Dallas Cowboys-Training Camp
Kelvin Kuo / USA TODAY Sports

The NFL may have run into its first major problem regarding a return to action amid the COVID-19 pandemic, as a new issue has popped up regarding testing. On Sunday morning, Tom Pelissero of the NFL Network reported that several NFL teams are altering or canceling football activities for Sunday after irregularities were found in results from Saturday's COVID-19 test results. The NFL released a statement regarding this latest development:

"Saturday's daily COVID testing returned several positives tests from each of the clubs serviced by the same laboratory in New Jersey.  We are working with our testing partner, BioReference, to investigate these results, while the clubs work to confirm or rule out the positive tests. Clubs are taking immediate precautionary measures as outlined in the NFL-NFLPA's health and safety protocols to include contact tracing, isolation of individuals and temporarily adjusting the schedule, where appropriate. The other laboratories used for NFL testing have not had similar results."

According to Brad Biggs of the Chicago Tribune, the Chicago Bears announced that Saturday's COVID-19 testing returned nine positive cases for players and staff -- and it was determined that all nine were false positives. Some teams such as Washington and the Indianapolis Colts hit the practice field on Sunday for an early morning workout, but others such as the Cleveland Browns decided to shut things down for the day just to be careful, according to Mike Garafolo of the NFL Network

This is not the first time the league has had to navigate through murky waters regarding testing, as it was discovered earlier this month that Detroit Lions quarterback Matthew Stafford and Los Angeles Chargers assistant Seth Ryan registered false positive COVID-19 tests. This caused the NFL to rework its protocols when it came to positive tests, and the league may need to make another change after they finish investigating what happened this weekend in their designated lab.