08:25 AM ET 09.01 | The NFL and its on-field officials' union began negotiating again Friday, hoping to end the lockout that resulted in replacement officials working the preseason. The league locked out the NFL Referees Association in early June, then hired replacements, whose work in exhibition games has been heavily criticized. There even was some optimism surrounding Friday's talks, as Michael Arnold, lead negotiator for the officials, said in a statement: "Reports on the economic gap between the NFL and NFLRA are inaccurate." League spokesman Greg Aiello said that statement was accurate. Earlier this week, NFL executive Ray Anderson said the regular season would open with replacement officials and that the league was prepared to use them "as much . . . as necessary" afterward. But the NFL has seen and heard the problems the replacements have had this summer, something that tests the integrity of the sport.