The NHL's chief medical officer is urging caution toward the league returning to play this season -- including the idea of playing in empty arenas.

"From a medical perspective, I think we'd have to understand what the risks are for the different groups," Dr. Willem Meeuwisse said on a call with reporters Wednesday. "What are the risks to the players? What are the risks to the staff that would be required to run an event? And what are the risks to the fans?

"Once we know what those things are, I think we can make a more intelligent decision."

The NHL's season has been on pause since March 12 due to the coronavirus pandemic, and the league is running several models of how it can complete the season -- if at all possible.

Meeuwisse said it is "very difficult to predict" a timeframe at this point.