In an essay on The Players' Tribune on Friday, Detroit Lions quarterback Matthew Stafford detailed racism against teammates that he saw firsthand in the spring while working out in Georgia.

Stafford wrote in the essay that he went to work out with receiver Danny Amendola one week at a field -- something he had prearranged -- and had no issues. The next week, Stafford showed up to the same field with the same permissions, this time with four Black teammates, and was told to leave.

"We were just starting to dump all the footballs out on the field and some of the guys were still stretching when a gentleman came out and told us that we were trespassing -- and to leave immediately. We didn't even have our cleats on yet. I remember I was standing there in my socks, just kind of stunned and confused, like, What?" Stafford wrote. "But he didn't even want to listen. We were still gathering up the footballs and trying to figure out another spot where we might be able to go when the gentleman pulled out his cellphone.

"He said, 'I'm calling the police.' After everything that we've witnessed over the last few months, and how situations can escalate for no reason at all ... and here the police are being called.

"We were there for maybe 10 minutes total. Nobody said a bad word to him. And he still called the police and told them that we were being 'uncooperative' and 'not leaving the property.'"

Stafford wrote that he and his teammates left immediately and that the quarterback was "embarrassed to have put my teammates in that situation."

He wrote, "The only difference is what we all know in our hearts. Danny and I are white. We don't get the cops called on us in those situations. We don't immediately get called uncooperative. And even if Danny and I somehow did get the cops called on us, we all know how that interaction would've gone."

Stafford wrote that in the day of meetings leading up to the team's decision to cancel practice in August in protest of the Jacob Blake shooting, the story that stuck with him was the one told by teammate Trey Flowers.

Flowers explained what he does if he is ever pulled over by police and how "he copes with the anxiety" of any dealings he has with law enforcement.

"Trey was explaining that if he were to ever get pulled over in his car -- something that I have experienced many times without even thinking twice about it -- he would roll down his window, put both hands on the wheel and ask the officer if he would like him to step out of the car so he can handcuff him," Stafford wrote.

"Just so that he is not seen as a threat. Just so the officer can't say, 'Oh, he was reaching here, he was reaching there.' ... Just so he makes it back home.

"If you're a white person, all I'm asking you to do is to really think about that. Imagine that being your first instinct when you see police lights in your rearview mirror. No one in America should have to feel this way."

Stafford said after the team's protest that he received text messages that opened his eyes to how far away he believes some people are from listening.

"Things like, 'Sorry you had to miss practice' or 'Sorry you have to deal with this stuff, man,'" Stafford wrote. "The fact that anyone would feel sorry for me, or be thinking about a football practice at a time like that, really speaks volumes.

"There are still people in this country who just want sports to be a distraction, and that's their right. But I beg to differ."

Stafford had long been quiet about many topics for the majority of his career. In the past six months, he has become vocal, from speaking in town halls on voting rights to donating money for social justice initiatives in Georgia -- where he went to college -- to the essay he wrote Friday.

"When something's important to him and he feels a certain way, he'll express his opinions and he'll do that," said Sean Ryan, Stafford's quarterbacks coach the past two seasons. "I think when he sees something that's wrong or something that he feels that he can help make right, he's going to do it.

"I've seen that from the start. I think situations have changed in the last year-and-a-half that have given him the ability or the situations that present maybe what he feels like, 'Hey, this is the time to voice my opinion.' So I think things have changed for a lot of us in that way. But it does not surprise me at all that the guy's out in front, that he's leading and that he's being genuine and letting his feelings be known and trying to help things. That does not surprise me at all."