Astros spotted wearing Black Lives Matter T-shirts during Opening Day

Major League Baseball's season begins for 26 more teams Friday. And more of them will be a part of baseball's postseason after MLB and the players' union agreed Thursday to an expanded playoff structure that includes 16 teams instead of the usual 10.

The Houston Astros begin their season at home against the Seattle Mariners. Most players and staff members were spotted wearing Black Lives Matter t-shirts during their preseason workout on Friday.

Another photo showed several players and coaches kneeling before the game as well.

The Astros are the latest Major League Baseball team to show their support for the movement.

The Associated Press contributed to this report.