The Chicago Cubs and Miami Marlinswill honor the victims of last month's mass shooting at Marjory Stoneman Douglas High School with a number of tributes during their season-opening four-game series.
Both teams wore patches with the initials "MSD" and 17 stars to honor the number of lives lost in the shooting.
The Cubs will host victims' families and survivors from Stoneman Douglas before Friday's game.
Chicago Cubs first baseman Anthony Rizzo, a Stoneman Douglas alumnus, hit a home run during an 8-4 victoryThursday, tapping his chest as he crossed home plate.
"I've hit a lot of home runs. That was probably the most out-of-body experience I've had hitting a home run, probably in my life," Rizzo said after the game. "My emotions on Opening Day are usually pretty high, but with all this, you can't really put it into words."
Rizzo said he put his hand on the Stoneman Douglas patch after rounding the bases and looked skyward.
"[I gave] a look up to those kids up there and the adults that lost their lives," Rizzo said. "It was a special moment for me, personally."
Rizzo said Friday would be an emotional day, as four families of victims or survivors are scheduled to throw out the first pitch.
"[Friday] will be a tough one to see for everyone who has a pulse," Rizzo said before Thursday's season opener.
Rizzo and the Cubs showed their support for Stoneman Douglas by wearing T-shirts made by manager Joe Maddon's Respect 90 Foundation.
"I want to show our support for the kids," Maddon said. "The entire activist movement by the youth of America. We love it. I love it. I think a lot of the players do also."
Rizzo echoed that message after watching the Stoneman Douglas baseball team win a game 15-0 on Tuesday night. He will host the team at Friday's game as well.
"These kids are standing up for what they believe in," Rizzo said. "They're motivating everyone to go out there to register to vote, which is amazing. ... They're holding the throttle down on these politicians and making them accountable."