Replacement refs prepped in NYC

Updated: September 9, 2012, 5:58 PM ET

By Chris Mortensen and Adam Schefter | ESPN

The NFL is preparing replacement referees as much as it possibly can, going so far as to bring 17 referees to New York this past week to watch Wednesday night's Dallas Cowboys-New York Giants regular-season opener with the league's head of officials, Carl Johnson, at the league's offices, according to sources.

The replacement referees returned to the NFL offices Thursday for a day of training with Johnson and the league.

So for two days, the NFL prepped the replacement referees as best as it could, in the event this lockout lasts into Weeks 2 and 3 of the regular season, as many around the league now believe it will.

The league was encouraged with what it saw from officials Wednesday night in the Cowboys-Giants game. The crew did miss some calls, but as one source noted, "The few mistakes they made could easily have been made by the regular referees."

The NFLPA, meanwhile, sent a letter to the league last week requesting the background checks the league did on the replacement officials, sources said, as well as information on how the investigations were conducted.

The NFLPA wants to ensure that replacement officials are held to the same standards as the regular officials and asked in the letter that the league end the lockout for the sake of player safety.

"We responded to the letter and said we would send that information to the union," NFL spokesman Greg Aiello said. "We see no evidence of player safety being compromised."