The petition was filed Monday in Minnesota, where the NFLPA has often gone to contest labor matters with the league.
The addition of two teams in the playoffs was discussed Tuesday at the league’s spring meetings, but several owners and team executives said no vote would occur.
“We’re in talks with a handful of players who are considering it,” the Ravens’ linebacker said. “There are up to four players being talked to right now and they’re trying to be organized so they can come out on the same day together.”
The NFL has made thigh and knee pads mandatory equipment for the 2013 season.