Neither the league nor the player's union would comment on how the talks went Wednesday, but both sides said there would be another round of meetings Thursday.
"A small group of NHLPA staff and players met today with two experienced FMCS [Federal Mediation and Conciliation Service] mediators," union chief Don Fehr said. "We expect that these discussions will resume on Thursday."
This was the first time mediators had joined the negotiations, which have netted no results since the current lockout of players began on Sept. 16. The two sides had not met in a week.
All scheduled regular-season games have been canceled through Dec. 14 -- a total of 422 contests.
The NHL is trying to avoid its second lost season in eight years.
Notable deaths of 2014 [PHOTOS]