The Green Monster sported a massive “Racism is American as baseball” banner last night as guerrilla activists staged a fourth-inning protest in the latest race-related incident at Fenway Park.

Four protesters were ejected, telling ballpark security on the way out that the message was inspired by the Black Lives Matter movement. No charges were filed, and the four left the stadium without further incident.

“During the fourth inning of tonight’s game, four fans unfurled a banner over the left field wall in violation of the club’s policy prohibiting signs of any kind of be hung or affixed to the ballpark,” the Red Sox said in a released statement. “The individuals involved were escorted out of Fenway Park.”

Immediately after the final out in the top of the fourth inning, the banner was draped near the middle of the Green Monster. It remained until just before the bottom of the inning, when ballpark security confiscated the banner and broomed the activists.

CSNNE’s Evan Drellich spoke to a protester who said there were five people involved from several activist groups: three held the banner in place, one documented the protest from up close and another documented from far away. The distant protester was not ejected.

“We see Boston continually priding itself as a kind of liberal, not racist city, and are reminded also constantly that it’s actually an extremely segregated city,” the protester said. “It has been for a long time, and that no white people can avoid the history of racism, essentially. So, we did this banner as a gesture towards that, to have a conversation about that.”

A U.S. military veteran was being honored by the Red Sox as the banner was unfurled, but the protester told Drellich that timing was coincidental. The incident lit up social media as baseball fans and activists weighed in pro and con.

Racism has become a heated topic around the Red Sox this season. On May 1, Orioles outfielder Adam Jones said that at least one Red Sox fan called him a racially derogatory term, and just days later, a fan was banned from Fenway Park for using a racial slur to describe a national anthem performance.

More recently, Red Sox owner John Henry told the Boston Herald in August that he planned to lead a movement to rename Yawkey Way due to former owner Tom Yawkey’s reputation for racial intolerance.

Red Sox right fielder Mookie Betts denounced the sign itself, but acknowledged its intended message was worthy of a larger conversation.

“There’s no place for that,” Betts said. “That’s for another day, though.”