As expected, controversial San Francisco 49ers quarterback Colin Kaepernick .opted out of the final year of his contract on Friday and became a free agent.

Kaepernick, 29, who sparked a nationwide debate last year by refusing to stand for the pregame rendition of the national anthem before 49ers regular season games in a protest against societal inequality, exercised his option to cancel a team-friendly 6-year, $126 million contracts signed in 2014.

Silent protest

Kaepernick's protest, in which he silently knelt along the sidelines instead of standing for the anthem as is traditional, attracted nationwide attention and inspired fellow athletes from the National Football League and National Basketball Association to join in.

But Kaepernick's stand also drew public push-back and criticism from other colleagues and from many football commentators.

Kaepernick was due to earn $14.5 million in 2017, according to the San Francisco Chronicle newspaper. The quarterback signed the big deal after leading the 49ers to the 2012 Super Bowl after starting quarterback Alex Smith was injured. They lost, 34-31, to the Baltimore Ravens in New Orleans. The following year, with Kaepernick behind center, the 49ers reached the NFL championship game.

Could be re-signed

But Kaepernick never was able to regain his championship form and was relegated to backing up Blaine Gabbert, who took over behind center. In fact, General Manager John Lynch and new Head Coach Kyle Shanahan told the newspaper that the 49ers would have released Kaepernick if he hadn't opted out of his contract.

But Kaepernick still could be re-signed as a free agent.

“I think we both agreed that under the current construct it wasn’t going to work out,” Lynch said. “But we said let’s not close the door . . . and it’s something that we left that door open in a very real and positive way.”

Progress acknowledged

Kaepernick said last week he had decided to give up his pregame protest for the 2017 season because progress had been made towards societal awareness of equality issues.

“When there’s significant change, and I feel that flag represents what it’s supposed to represent, and this country is representing people the way that it’s supposed to, I’ll stand,” he said last year after the 49ers first preseason game.

Kaepernick reportedly has followed through on his pledge to donate $1 million to charities benefiting the underprivileged through his Colin Kaepernick Foundation, the newspaper said.