What you need to know:
- Kaepernick protested police brutality and racial inequality by kneeling in 2016 but has not been signed by a team since that season.
- "You see firsthand how somehow sticking up for something they believe in, what it can do to you in the sports realm," Minnesota Vikings running back Alexander Mattison said in a post on the NFL's website.
NFL stars Tom Brady, Dak Prescott and Drew Brees and NBA coaches Steve Kerr and Gregg Popovich were among more than 1,400 people from America's largest sports leagues who on Wednesday supported an end to qualified police immunity.
The Players Coalition submitted the letter to US lawmakers supporting passage of the Amash-Pressley bill, which seeks to make it easier to sue police officers for brutality, among other things.
The bill would close what has been seen as a loophole allowing police and government officials to avoid civil suits in federal court.
Major League Baseball stars Giancarlo Stanton and Matt Kemp, retired star pitcher C.C. Sabathia, NFL receiver Odell Beckham Jr., NFL safety Justin Simmons and NBA guard J.J. Redick were also among the players, coaches and executives who signed the letter to the US Congress.
The athlete support comes in the wake of the police killing of George Floyd and the global protests that followed.
"We are tired of conversations around police accountability that go nowhere and we have engaged in too many 'listening sessions' where we discuss whether there is a problem of police violence in this country," the letter from athletes said.
"There is a problem. The world witnessed it when Officer Chauvin murdered George Floyd and the world is watching it now, as officers deploy enormous force on peaceful protestors like those who were standing outside of the White House last week.
"The time for debate about the unchecked authority of the police is over -- it is now time for change."
The Coalition traces its origins to 2016 when five NFL players spoke to US lawmakers about racial inequality and criminal justice reform.
NFL commissioner Roger Goodell last week said the league had been wrong to silence player protests such as the anthem kneeling started by former NFL quarterback Colin Kaepernick.
The league condemned racism and oppression of black people and admitted "we were wrong for not listening to NFL players earlier and encourage all to speak out and peacefully protest."
Kaepernick protested police brutality and racial inequality by kneeling in 2016 but has not been signed by a team since that season.
"You see firsthand how somehow sticking up for something they believe in, what it can do to you in the sports realm," Minnesota Vikings running back Alexander Mattison said in a post on the NFL's website.
"We've had enough. Before, guys were scared to lose their jobs, scared of being fined, all of that. Now, it's kind of a thing where, if you're going to fine one of us, you're going to fine all of us. If you're going to get rid of one of us, you're going to get rid of all of us.
"There's strength in numbers. It's bigger than just black people saying this. This is a problem in the world that we're looking at. Everybody is coming together. They're stepping up and letting their voice be heard."