NEW YORK -- With the issue of supplementary discipline a large part of the Wednesday's agenda, talks grew increasingly contentious between the NHL and NHL Players' Association during Day 2 of labor negotiations.

Mathieu Schneider, special assistant to NHLPA executive director Donald Fehr, wouldn't go so far as to characterize the negotiations as "adversarial," but he did concede that there were some tense moments between the two camps.

"At times there have been heated exchanges," Schneider said. "There's definitely strong opinions on both sides, especially when it comes to supplementary discipline, but I wouldn't describe it as adversarial. Not at all."

NHL deputy commissioner Bill Daly similarly downplayed the tension and described the discussions as "lively."

"I wouldn't characterize it as tense, I really wouldn't," Daly said.

"People had strongly-held views, and we heard some players in particular, how important this issue is to them. That didn't surprise anybody at our end of the table. Actually, I thought it was a good, lively discussion. I didn't feel tense at any point."

Both league disciplinarian Brendan Shanahan and fellow members of the NHL's Department of Player Safety Stephane Quintal and Rob Blake were involved in Wednesday's subcommittee meeting on supplementary discipline. Schneider declined to disclose the specific gripes the players have with the current system, but he made it clear that they'd like to see some changes.

"I don't think we'd be discussing it if we were satisfied with it," Schneider said.

Although the two sides recently have found common ground in other areas -- legal and health and safety issues, for example -- supplementary discipline may be among the most polarizing of the "non-core" economic issues that must be brokered should they come to a new deal.

"I wouldn't characterize it as divisive," Daly said. "I would suggest that, based on what we've heard at this point of negotiations now that we've been at this a month and a half, it seems to be an important issue for the players."

It is believed the NHLPA would like to see an independent arbiter involved in some capacity on issues of supplementary discipline, especially those that carry significant financial penalties, although Daly said the appeals process was not a large part of the day's discussions. He anticipates that will be a significant issue that must be addressed in the near future, although Wednesday's meeting dealt with the supplementary discipline process as a whole.

"I think it's more changes they'd like to see made," Daly said. "I think the objectives that they have in their changes are objectives we share. We just believe that the supplementary discipline process works. It's a tough process, but it works fairly well and I'm not sure some of the changes they've proposed would necessarily improve it.

"Again, I'm not pre-judging that. It's something we have to talk through with them, and we come at that with an open mind."

With talks and tensions ratcheting up, Fehr is expected to return Thursday from Europe, where he briefed players on the proceedings thus far. Discussions over the main financial issues -- salary givebacks, hockey-related revenue and revenue-sharing -- likely will resume Thursday and Friday at league offices in midtown Manhattan.

That should provide a telling glimpse into how far apart the two sides are and the likelihood of a new deal before Sept. 15, when the current collective bargaining agreement expires.

"We're missing a key part of this negotiation, which is where they sit on the economic issues," Daly said. "So, until we hear from them on the important economic issues, it's tough for me to forecast what the future may hold."