The owners argued in the filing that Nelson's injunction "undercut" their leverage by allowing the players to circumvent the lockout and further delayed constructive bargaining talks, which they deemed "the essence of irreparable harm."
"As to harm to the NFL, federal labor law permits an employer to institute a lockout 'for the sole purpose of bringing economic pressure to bear in support of his legitimate bargaining position,' " the attorneys wrote.
Also on Monday, the NHL filed a brief in support of the NFL. Labor strife caused the hockey league to cancel its 2004-05 season and the current collective bargaining agreement expires in 2012.
"While the facts and circumstances may differ as between our league and the NFL, the issues presented on this appeal are of central importance to the NHL and to all participants in collective bargaining relationships in the United States," NHL attorneys wrote.
