"United We Stand" rally for Kaepernick, organized by several civil rights groups, will start at 5pm (2100 GMT) on August 23 outside the NFL headquarters.
According to a social media post by Lee on Tuesday, the "United We Stand" rally for Kaepernick, organized by several civil rights groups, will start at 5pm (2100 GMT) on August 23 outside the NFL headquarters on Park Avenue in New York City.
"I Did Not Organize And Set Up This Protest. However I Still Support My Brother And His Stance On The Injustices In The USA," Lee said in a separate Twitter post.
Kaepernick, the former San Francisco 49ers signal caller, remains unemployed a month before the start of the regular season.
The Seattle Seahawks are the only team that has hosted Kaepernick since he opted out of his contract with the 49ers and became a free agent.
Lee and others have suggested that teams are avoiding Kaepernick, who was 2-10 as a starter with the 49ers last season, because of his anthem protest.
NFL commissioner Roger Goodell denied this month that Kaepernick was being "blackballed" but Seahawks wide receiver Doug Baldwin said last week that he believes NFL owners are "trying to send a message" by not signing Kaepernick.
"It's frustrating because you want to have guys who are willing to speak out about things that they believe in, whether you agree with it or not," Baldwin told ESPN.