share: digg facebook twitter WASHINGTON (AP) — The New York Giants' John Mara joined the NFL group negotiating with the players' union Tuesday, the first team owner to participate since a federal mediator began overseeing the talks. Atlanta Falcons president Rich McKay, chairman of the league's competition committee, and Washington Redskins general manager Bruce Allen also were among those joining NFL Commissioner Roger Goodell when mediation resumed Tuesday at 1 p.m., 59 hours before the current collective bargaining agreement was due to expire. When that round ended Thursday, mediator George Cohen said the league and the NFL Players Association still had "very strong differences" on the "all-important core issues." Among the other significant topics in negotiations: a rookie wage scale; the owners' push to expand the regular season from 16 games to 18 while reducing the preseason by two games; and benefits for retired players. [...] if regular-season games are lost in 2011, the NFL figures that revenue losses would amount to about $400 million per week. If the league locks out the players, everything would stop except the NFL draft on April 28-30, and any interviews or workouts teams hold for college players leading up to the draft.