56
Yes
All NFL teams can start the football preseason with 80 player on their roster. As the regular season approaches, teams must start to cut down the number of players and 10 days before the season begins, all teams must be at 53 players on there active roster with (I believe) 6 or 8 player on there practise squad. Right now the Rams have 83 or so players on their roster and must be down to 80 on July 28th when they start camp.
october
august
October 31st
pre-seeson starts in mid-September and the regular season starts early in October
October 7 for the regular season September 21 for the pre-season
Each team has 15 players, so there would be 30 players in total at the start of the match.
There was a lockout due to no contract between the players and owners and the start of the 1998-99 season was delayed. Once a contract was agreed to, in early 1999, the season began and teams played a 50 game regular season schedule.
As of the start of the NFL preseason, NFL teams, including the Dallas Cowboys, typically have a roster limit of 90 players. To reach the regular season limit of 53 players, the Cowboys would need to cut 37 players. However, the exact number may vary depending on trades, injuries, or roster moves leading up to the final cutdown day.
1970.
Hockey started requiring helmets for players in the NHL in the 1979-1980 season.