There was a lockout of NFL players in 2011. There might be another in 2021.

NFL Players Assocation executive director DeMaurice Smith said Thursday the union will "prepare for war" over the next three years.

Smith and a panel of player union reps met with reporters Thursday at Super Bowl 52 in Minneapolis. When asked point-blank if there would be any consideration to extend the current collective bargaining agreement before it expires in 2021, Smith replied with a simple, "No."

Media: Is there a possibility that the current CBA will be extended?@DeSmithNFLPA: No. pic.twitter.com/hMUzcPHWHn
— NFLPA (@NFLPA) February 1, 2018

Smith did say he would leave open the possibility of beginning early negotiations with the NFL about the next CBA.
There are several issues players have with the current CBA, the first of which is the power given to commissioner Roger Goodell. Player safety is another issue, especially with things the NFL controls — like Thursday night games and talks of an 18-game regular-season schedule.
Smith spoke with Goodell about making Thursday games safer, and concussions remain a concern.

"The goal of the concussion protocol is to improve the care that players were given," Smith said.
Bengals tackle Eric Winston, who is the NFLPA president, has been a staunch opponent of an 18-game schedule and reiterated his opposition to an expanded schedule on Thursday. He added that he will "never be happy with the concussion protocol."
"There will always be progress to be made," Winston added. "I think that's important. I think that is valuable."

Player safety was just one topic discussed Thursday. Smith said he has spoken with Goodell about the rights of players to express themselves during the national anthem. He said he doesn't know if the majority of owners would vote to make changes to the NFL's anthem policy, but that Goodell and Giants owner John Mara have expressed support for the players’ right to protest.

Smith also scoffed at the idea that lower television ratings were tied to player protests.
"To try to pin declining ratings on any single thing is to be intellectually dishonest," he said.

Winston said players like former 49ers quarterback Colin Kaepernick, who went unsigned in 2017 after kneeling during the national anthem the entire 2016 season, taught players how much power they have "to move the needle on social progress."

That mantle was picked up by Eagles players Malcolm Jenkins and Chris Long, who was the recipient of the NFLPA Byron "Whizzer" White Community MVP Award for donating his 2017 salary to charity