Report: NFL's 77 presumptive positive COVID-19 cases return negative

The NFL re-ran overnight a total of 77 tests for COVID-19 from its teams using the same laboratory in New Jersey and all results returned negative, a source told ESPN's Adam Schefter.

All 77 presumptive positives cases from Saturday's irregular results have now reportedly returned negative twice after the league re-ran them earlier Sunday evening.

The NFL began investigating the positive tests after the 11 teams using one of the five laboratories were affected. The impacted clubs included the Cleveland Browns, Chicago Bears, Buffalo Bills, Detroit Lions, Pittsburgh Steelers, Minnesota Vikings, New York Jets, Green Bay Packers, New England Patriots, and New York Giants.

The Vikings had 12 false positives this weekend, while the Jets accounted for 10.

Both the Bears and Browns postponed their morning practices to Sunday afternoon after learning about the situation. Cleveland head coach Kevin Stefanski revealed Monday he was one of the individuals within the Browns organization who received a false positive.

"It wasn't fun to have that phone call early in the morning," Stefanski said, according to Field Yates of ESPN.

The Bills didn't change their Sunday practice schedule, but they were without all the players whose test results initially returned positive, including quarterback Josh Allen.

No new players have been added to the NFL's reserve/COVID-19 list, which currently includes just three players.

BioReference Laboratories, the lab used by the 11 affected teams, stated the testing issue stemmed from "an isolated contamination during test preparation in the New Jersey laboratory."

"Reagents, analyzers, and staff were all ruled out as possible causes and subsequent testing has indicated that the issue has been resolved," lab executive chairman Jon R. Cohen said in a statement obtained by NFL Network's Tom Pelissero.

The league is now working with the lab on ways to immediately re-test players and coaching staff while avoiding lag time for results, according to Ian Rapoport of NFL Network.