As several NBA teams traveled to Florida on Tuesday, NBA commissioner Adam Silver expressed concern that potential positive coronavirus cases following quarantine inside the league's campus setup will reveal "in essence a hole in our bubble."

In a virtual interview with Fortune Brainstorm Health, Silver said the NBA expects more positive coronavirus cases to pop up as teams arrive to the NBA campus at Walt Disney World resort this week. But once teams arrive, all personnel will be tested and must quarantine for at least two days.

"We won't be surprised when they first come down to Orlando if we have some additional players test positive," Silver told Fortune Brainstorm Health. "What would be most concerning is once players enter this campus and then go through our quarantine period, then if they were to test positive or if we were to have any positive tests, we would know we would have an issue."

"... We would know that there's in essence a hole in our bubble or that our quarantine or our campus is not working in some way," Silver added later. "So that would be very concerning."

Silver said any significant amount of positive cases inside the protected campus could result in a second shutdown of the NBA season. Several teams, including the Brooklyn Nets, Denver Nuggets, LA Clippers, Miami Heat, Milwaukee Bucks and Sacramento Kings, have closed their practice facilities in the past week due to positive coronavirus cases among their respective travel groups.

"We began testing all our teams roughly two weeks ago and as we reported we had a significant number of positive cases," Silver said. "I think that is more a representation of what is happening around the country."

Florida's Department of Health reported 7,347 additional positive cases on Tuesday. The state's total is now at 213,794.

Silver said the NBA's campus, with daily testing and guidance from medical experts, is "as protected as possible from the environment around us."

"So on paper, and dealing with our experts, this should work," Silver said. "But we shall see. I'm confident based on the positive cases we are seeing from our players and the general public around the country that it will be safer on this campus than off this campus in part because we are going to be doing daily testing.

"But again, this virus has humbled many, so I am not going to express any higher level of confidence than we are following the protocols, and we hope it works as we designed it."

Silver reiterated that the league likely will not be forced to shut down again due to one potential positive coronavirus test inside campus. However, a spread could bring the NBA to a halt again.

"I think we do have the ability to trace, of course to try to understand where that positive case came from," Silver said of any positive cases inside the Walt Disney World campus. "We can actually analyze the virus itself and try to track whether there is more than one case, if it's in essence the same virus and same genetic variation of the virus that is passed from one player to another or two people have gotten it on the campus independently. So those are all things that we are looking at.

"Certainly if we had any sort of significant spread within our campus, we would be shut down again."