With today's announcement, that the Ottawa Senators had postponed their next three games due to a COVID-19 outbreak, this triggered the NHL's ability to withdraw.
The NHL's priority is to finish a full 82 game season and they will not allow the Olympics to get in the way of that. It is also historically documented that the NHL prefers not to be involved in the Olympics, so this opportunity might allow the league an escape from a deal they felt forced to make to save face.