Very strong differences remain between the NFL and NFLPA as the current collective bargaining agreement stands to expire next Thursday. Talks will continue in front of a federal mediator on Friday, before resuming on Tuesday -- just 48 hours prior to the expiration. All parties have agreed to cut off contact with the media as they continued working out their differences. Past and present NFL front office leaders, sports agents and business experts interviewed during the past week by the Pittsburgh Tribune-Review predict a labor stoppage that could cut into the season's opening weeks.