Birch noted the union has asked for appeals to be handled by a neutral, third party, and that the league has proposed third-party arbitration since 2009. In MLB, positive tests and resulting discipline can be challenged by the union before an arbitrator.
MLB and its players' union agreed before the 2012 season to start releasing the identity of substances causing a player's positive test. Birch was asked whether use of the drug Adderall is a trend in the NFL or an excuse used by players who tested positive for performance enhancers.
"That is one of the features we have proposed is to release the substance that was tested for so there is no ability to go behind and minimalize what the violation was," Birch said. "I think it also helps other players realize what substances cause this.
"But the union has consistently rejected that, so that's another feature they said they'd take today from Major League Baseball and that they've rejected today."
Union spokesman George Atallah disputes Birch's claim.
"It's part of our collective bargaining agreement to keep everything confidential," Atallah said. "Part of the reason why it's kept confidential is if a player needs some sort of treatment, he can get treatment without public pressure."