ESPN 49ers reporter Nick Wagoner says that Colin Kaepernick expressed his intention to continue the conversation moving forward and adds that Kaepernick was able to speak to his teammates in a players-only meeting. (1:49)

MINNEAPOLIS -- While a former teammate who caught passes from Colin Kaepernick defended the San Francisco 49ers quarterback's decision not to stand for the national anthem, a former teammate who blocked for Kaepernick didn't see it that way.

Minnesota Vikings guard Alex Boone, who played five seasons with Kaepernick in San Francisco before leaving in free agency last spring, called it "shameful" that Kaepernick did not stand for the national anthem on Aug. 26 against the Green Bay Packers, adding "we probably would have had a problem on the sideline" had the quarterback done it while Boone had still been his teammate.

Former 49ers receiver Anquan Boldin said Sunday that "you still have to respect" Kaepernick's opinion "even if you don't agree with what someone does." The quarterback told NFL Media on Friday that his decision was meant as a form of protest over the treatment of "black people and people of color" in the U.S.

While Boone acknowledged that Kaepernick "can do whatever he wants," he added, "there's a time and a place. Show some respect."

"You should have some f---ing respect for people who served, especially people that lost their life to protect our freedom," said Boone, whose brother J.J. served with the Marines in Iraq. "We're out here playing a game, making millions of dollars. People are losing their life, and you don't have the common courtesy to do that. That just drove me nuts.

"Anquan said it this morning [that Kaepernick had the right to do it], and I was kind of mad that he said it, because I was like, 'God, if Anquan says it, I've got to go with it,' because Anquan was such a leader, and he's a smart guy. He gets it. But at the same time, I was upset with his choice to do that and kind of disrespect the flag."

Vikings guard Alex Boone, who played five seasons with Colin Kaepernick in San Francisco, said the two "probably would have had a problem on the sideline" had the quarterback sat the national anthem while Boone was a member of the 49ers. Kirby Lee-USA TODAY Sports

Niners coach Chip Kelly said Kaepernick also didn't stand for the anthem on Aug. 20 against the Denver Broncos, telling reporters, "We recognize his right to do that. So, it's not my right to tell him not to do something. That's his right as a citizen.

"We recognize his right as an individual to choose to participate or not participate in the national anthem."

Boone, though, said the gesture was disrespectful to the American flag and those who serve in the military.

"You see all these pictures of these veterans that have no legs, and they're standing up in a wheelchair," Boone said. "I had a brother that served, and he lost friends. I know how much it means to him. It's shameful."

"We're out here playing a game, making millions of dollars. People are losing their life, and you don't have the common courtesy to do that. That just drove me nuts."

New York Giants wide receiver Victor Cruz said after his team's exhibition victory against the New York Jets on Saturday night that the American flag deserves respect -- no matter the circumstances in the U.S. or beyond.

"The flag is the flag," Cruz said. "Regardless of how you feel about things that are going on in America today, and the things that are going on across the world with gun violence and things of that nature, you've got to respect the flag, and you've got to stand up with your teammates. It's bigger than just you, in my opinion. I think you go up there, you're with a team, and you go and you know you pledge your allegiance to the flag and sing the national anthem with your team, and then you go about your business, whatever your beliefs are.

"Colin is his own man. He decided to sit down and that is his prerogative, but on a personal standpoint, I think you have to stand up there with your team and understand and it's this game and what's going on around this country is bigger than just you."

Buffalo Bills coach Rex Ryan said Sunday he believes players and coaches should stand for the anthem to show respect and give thanks to members of the armed forces.

"You've got to look at the gifts that we have, the opportunity that we have to play a great game is through the men and women that serve our country," Ryan said before practice on Sunday. "And I think that's an opportunity right there just to show respect."

Information from The Associated Press was used in this report.