"Today's practice has been canceled and all meetings will be conducted virtually," the team said in a statement. "The player who tested positive and all close contacts have been contacted and have already begun self-isolation."
The team later announced it had received clearance from the NFL to re-open its facility and hold practice on Friday, as scheduled. The club remains in the league's intensive COVID-19 protocol.
The Bears announced Tuesday they had placed Jason Spriggs and Germain Ifedi on the reserve/COVID-19 list. The designation alone isn't confirmation of a positive test since it can be used for players who only had close contact with a person who carried the virus.
Chicago is scheduled to play the Tennessee Titans on Sunday.
So far, the game doesn't appear to be in jeopardy, and Titans head coach Mike Vrabel isn't letting Thursday's news affect his squad's preparations.
"We've been through this," Vrabel told reporters. "We'll continue to prepare like as if we're playing on Sunday until we hear otherwise. I can't speculate on what happened or didn't happen."
Earlier in the year, an outbreak within the Titans forced the NFL to shift some of their games around.