The NFL remains hopeful of starting its regular season on time, but its chief medical officer, Dr. Allen Sills, says that certain prerequisites must be met.

Specifically, Sills says widespread testing for the coronavirus must be available.

Jeff Pash, the NFL's general counsel, told reporters on Tuesday that the "expectation" is to begin the regular season as scheduled in September.

"I think what was implied there [by Pash] was to say we are not at a point where we are saying that is absolutely not going to happen so we should continue our planning and preparations as if we're going to be able to do that," Sills said.

"But obviously we're going to have to evaluate that along the way. And follow what the recommendations are from public health officials and from our infectious-disease experts and others."