Megan Rapinoe kneels during anthem prior to USWNT friendly

With all of her teammates standing, U.S. women's national team midfielder Megan Rapinoe knelt for the national anthem Thursday before playing Thailand in a friendly soccer game.

She described the gesture as a show of solidarity with San Francisco 49ers quarterback Colin Kaepernick protesting social inequalities in the African-American community.

Sport Illustrated's Grant Wahl tweeted: "Megan Rapinoe takes a knee for the national anthem in a US uniform. Unprecedented in international soccer history based on my research."

This is not the first time that Rapinoe has knelt during "The Star Spangled Banner." She first took a knee during the national anthem prior to a Sept. 4 game with the Seattle Reign, the team she plays for in the National Women's Soccer League.

In her next game with Seattle on Sept. 7, the NWSL's Washington Spirit played the anthem prior to the players taking the field to preclude a repeat protest.

While she stood alongside other non-starters for the national anthem of Thailand at Mapfre Stadium in Columbus, she knelt when an Air Force servicewoman began to sing the American anthem.

There was little noticeable reaction from the crowd in attendance for the game.

Although Rapinoe was the only player to kneel, her teammates remained close by her on either side.

U.S. coach Jill Ellis told ESPN before the game that although she supported Rapinoe's social activism, she did feel that it is expected for every national team player to stand for the national anthem.

The 31-year-old has used the visibility of the national team to address off-field issues. She was one of five players named in an equal-pay complaint filed against U.S. Soccer, and was also a vocal critic of artificial turf that was used for the 2015 FIFA Women's World Cup.

Although Rapinoe has not started a game since tearing an ACL last December, she came on the field as halftime sub Thursday. The U.S. beat Thailand 9-0

The U.S. women's national team plays its next game on Sunday in Atlanta against the Netherlands.