SACRAMENTO (CBS13) — The sudden retirement of a San Francisco 49ers rookie linebacker is sending shockwaves from National Football League through the youth leagues.

Chris Borland, 24, announced his retirement on Monday citing concussion concerns. He was seen as the heir apparent to linebacker Patrick Willis, who also retired abruptly after missing time with a turf toe injury during the 2014 season.

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The debate over the dangers of football isn’t new, but Borland’s move is unprecedented. At 24, he’s willingly leaving millions of dollars on the table, saying he doesn’t believe the long-term health risks are worth it.

Katie Fisk already didn’t want her son playing football, and now the Sacramento mom is even more certain.

“I’m not inclined to let my son play so early and so young. He’s only 9,” she said.

Sacramento Junior Dragons coach Lorenzo Walsh worries Borland’s abrupt retirement could be a turning point—wavering parents could be convinced to keep their kids away from a sport some increasingly believe is too dangerous.

“There are gonna be a lot of concerned people, parents,” he said.

Youth football signups are right around the corner.

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“It’s gonna have a big impact. There are gonna be a lot of concerned parents. Some aren’t going to sign their kids up for football,” he said.

It’s new science, but research suggests repetitive blows to the head can lead to long-term brain damage known as chronic traumatic encephalopathy.

Bennet Omalu, the local neurologist who discovered CTE said playing high-impact sports increases the risk of brain damage. The younger you start, he says, the greater the risk .

Walsh says teaching proper technique minimizes the danger and believes for his players that the benefits of the game he loves outweigh the risks.

“We’re in an inner-city at-risk program with 200 kids. We provide a positive environment for them to learn structure; discipline; work ethic,” he said.

But as one now-former 49er clearly felt, it might not be worth it.

“Concussions first and foremost, and as much as they have protective gear on, it’s not 100 percent,” Fisk said.

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Pop Warner signups are already down 10 percent in the last two years.