While the group knelt behind the bench, several other players placed a hand on a kneeling teammate's shoulder in support.
"There's a lot of racial and social injustices in the world that are going on right now," rookie safety Jabrill Peppers said after the Browns' second win in two preseason games. "We just decided to take a knee and pray for the people who have been affected and just pray for the world in general."
Players said linebacker Christian Kirksey led the prayer.
"We did it out of respect," Kirksey said. "No disrespect for anyone, we just felt like it was the right time and the need to do it."
Tight end Seth DeValve, who became the first known white NFL player to take a knee during the national anthem, said recent events in Charlottesville, Virginia, had a lot to do with the decision. But DeValve said it was also more involved. His wife, Erica, is African-American.
"I myself will be raising children that don't look like me, and I want to do my part as well to do everything I can to raise them in a better environment than we have right now," DeValve said. "So I wanted to take the opportunity with my teammates during the anthem to pray for our country and also to draw attention to the fact that we have work to do."
Those who took a knee were DeValve, running backs Duke Johnson Jr. and Terrence Magee, safeties Peppers and Calvin Pryor, cornerback Jamar Taylor, receivers Kenny Britt and Ricardo Louis, linebackers Kirksey and Jamie Collins, and running backs Isaiah Crowell and Brandon Wilds (who were not in uniform).
Wilds' participation was originally overlooked but was confirmed by the team after the game, bringing the count to an even dozen players.
Those who stood nearby included punter Britton Colquitt (who also had his hand on his heart), cornerback Jason McCourty, quarterback DeShone Kizer, defensive tackle Trevon Coley and offensive tackle Shon Coleman.
This past week, coach Hue Jackson stood by his players' right to make a statement, provided it was peaceful and he had advance notice.
"We respect our players; we respect the flag," Jackson said Monday night. "Those guys came to me and talked to me about it before they ever made a decision to do it."
Said Peppers, "We were not trying to disrespect the flag or be a distraction to the team, but as men we thought we had the right to stand up for what we believed in, and we demonstrated that."
Players said they had not thought past this game, so they could not say whether it was a one-time thing or if it will continue.
"It saddens me that in 2017 we have to do something like that," DeValve said. "I personally would like to say that I love this country. I love our national anthem. I'm very grateful to the men and women who have given their lives and give a lot every day to protect this courtly and serve this country. I want to honor them as much as I can.
"The United States is the greatest country in the world. It is because it provides opportunities to citizens that no other country does. The issue is that it doesn't provide equal opportunity to everybody.
"I wanted to support my African-American teammates today who wanted to take a knee."