San Francisco 49ers cheerleader takes a knee during national anthem before NFL game vs Oakland Raiders

Kneeling during the anthem has become a form of protest among some NFL players since then-49er Colin Kaepernick began the movement as a protest against racial injustice two seasons ago

A San Francisco 49ers cheerleader was pictured kneeling during the United States national anthem at a National Football League game on Thursday.

The San Francisco Chronicle was among several media outlets that published a tweeted photo of the unidentified woman on her right knee before the game against the Oakland Raiders at Levi's Stadium in Santa Clara, California.

The newspaper said the team did not comment on the matter.

Kneeling during the anthem has become a form of protest among some NFL players since then-49er Colin Kaepernick began the movement as a protest against racial injustice and police brutality two seasons ago.

Thursday's incident is believed to be a first by a cheerleader.

Quarterback Kaepernick has been without a team since March of last year, and has filed a grievance claiming the league's owners have colluded to keep him out of work.