ST. LOUIS -- In an empty stadium but with the country watching as baseball began a regular season like no other, Matt Carpenter was the first one on the field Friday to take grounders at third base. What he was wearing, and what most of the Cardinals were wearing as they trickled out of the clubhouse for batting practice, was a show of support for their Black teammates.

“BLACK LIVES MATTER” was written in block letters on black T-shirts that players and coaches were wearing before Friday’s season opener at Busch Stadium.

“It’s about solidarity,” manager Mike Shildt said during a pregame Zoom media session while wearing the shirt. “It’s creating awareness. There’s a lot of thoughts about the [Black Lives Matter organization]. For me, it’s more about what it represents, in total, just making sure that we continue to look to treat people fairly.”

The Cardinals and Pirates participated in a pregame ceremony to promote social justice. Following a video put together by the Players Alliance and a recorded narration by actor Morgan Freeman that emphasized equality and empathy, players from both teams held a 200-yard black fabric as a sign of unity. Players and coaches had intended to kneel for a moment of silence before the national anthem, but there was some confusion caused by the timing.

Opening Day starter Jack Flaherty wore his Black Lives Matter shirt throughout his warmups and the pregame introductions and ceremonies. The inverted MLB logo -- BLM -- with a black silhouette was stenciled on the mound Friday as Flaherty made his start.

"That was something that has been on my mind for a long time, that I was going to do that and probably will continue to do throughout the season," Flaherty said after the game. "I know eyes are on me at that point. And I just wanted to make it known and have any chance I can to bring awareness to it. I felt like wearing it and having that opportunity, I should take advantage of it.”

The Cardinals have had multiple clubhouse conversations about what they can do to promote social justice. The club brought in Turan Mullins, assistant dean and director of the office of diversity and inclusion at Maryville University in St. Louis, on Monday to discuss social justice and African American history. President of baseball operations John Mozeliak said having Mullins speak spurred conversations in the clubhouse between all players and coaches.

In a team meeting this week, Flaherty, Dexter Fowler and Willie McGee spoke. They told the team that it would mean a lot to them if players would join them in the movement, Adam Wainwright said. That’s what convinced Wainwright, whose adopted 1-year-old son Caleb is Black, to wear the shirt and show his support.

“You don’t have to tell me anything else besides that,” Wainwright said. “When my teammate looks at me and says he’s in need, he needs me to stand up for him, that’s great. I can tell you what that shirt meant to me was not having to do with anything outside of what’s in this clubhouse. And what’s inside of us as human beings, that had everything to do with supporting my Black brothers and sisters around the country, and especially my teammates and my close friends and my son.

“So when Dexter says, 'this would mean a lot to me, for you to join us in this movement,' it was actually my suggestion to the team that we need to stand up and support these guys. Because it’s not about us. This movement is not about me, the middle-class white guy, whatever. It’s not about anybody but the people who are struggling with what they’re struggling with.”