At least seven NFL players have taken to the field in protest of the use, or lack thereof, of rubber footwear during games.
According to NFL Players Association spokesman Michael Signora, the players will not play for the San Francisco 49ers or the Jacksonville Jaguars.
The players are concerned about safety for players who may be injured by players being forced to use rubber in the event of an emergency, Signora said.
The players are also upset that the league office has not yet agreed to use a “rubber” rubber boot, which they argue would prevent players from wearing the footwear in the field.
Signora did not say whether the players would have to wear the boots during games if the league did so.
Players are also concerned that the use is “unsafe,” and that the rubber does not absorb water and could easily be rubbed off.
They say the rubber should be replaced by a different material.
On Wednesday, the league announced that it would begin requiring all players to wear rubber boots in games.
The NFL also has begun offering gloves to players.
The league is not removing the gloves, but it is making the use mandatory for the first time in its history.