The Milwaukee Brewers and Cincinnati Reds refused to play their Major League Baseball fixture on Wednesday, mirroring a boycott by the NBA's Milwaukee Bucks following the police shooting of an unarmed black man in the teams' home state.
A statement by the Brewers said the teams had opted not to play on Wednesday in protest of the shooting of African-American Jacob Blake in Wisconsin on Sunday.
"The players from the Brewers and Reds have decided not to play tonight's baseball game," the statement said.
"With our community and our nation in such pain, we wanted to draw as much attention to the issues that really matter, especially racial injustice and systemic oppression."
Brewers closing pitcher Josh Hader had signaled a likely boycott earlier Wednesday before the team met to discuss the issue.
"I think it's a tremendous stand. This is more (than) about sports," Hader was quoted as saying by USA Today.
Other teams across MLB also opted not to play on Wednesday, with the Seattle Mariners voting not to take to the field in their game against the San Diego Padres in Southern California.
"There are serious issues in this country," wrote Mariners' African-American second baseman Dee Gordon.
"For me, and for many of my teammates, the injustices, violence, death and systemic racism is deeply personal.
"This is impacting not only my community, but very directly my family and friends. Our team voted unanimously not to play tonight."
The Los Angeles Dodgers game at the San Francisco Giants was also postponed, according to US media reports.
A Los Angeles Angels game at Houston set for Wednesday was postponed due to the approach of Hurricane Laura.
The NBA was forced to postpone its entire slate of playoff fixtures on Wednesday after the Bucks refused to take to the court for their game against the Orlando Magic.
It followed a wave of anger that swept across the NBA after the shooting of Blake on Sunday.
Blake was shot seven times in the back by police in Kenosha as he attempted to get into a car containing his three children.
Protests have erupted in Kenosha since the shooting, with two people killed after a man in civilian clothes opened fire on demonstrators with an assault rifle on Tuesday.