Bryce Huff retired from the NFL in March at age 27, six years after entering the league as an undrafted free agent and two years after signing a three-year, $51 million deal with the Philadelphia Eagles. He told The Athletic's Vic Tafur the decision wasn't sudden, though, and that he and his older brother, Jordan, had been considering it for a couple of years while building a startup on the side.

That company, Naberstone, focuses on suppressing lithium-ion battery fires without releasing toxic chemicals. It's a problem Huff says is growing as batteries become more common in everything from cars to power tools.

"I feel like we're going to save a lot of lives and protect a lot of companies," Huff said of the venture.

Self-funded by Huff, Naberstone has six employees, one major customer already on board, and is in talks with the U.S. military and recycling groups across Europe and Asia, according to the report.

Huff was traded from the Eagles to the 49ers in June 2025 and, after Nick Bosa's Week 3 knee injury, finished the season tied for the team lead with four sacks and 15 quarterback hits. But he said the idea of walking away was already on his mind before he reported to Santa Clara.

"I knew we would be able to help a lot of people, and the monetary upside was there as well," Huff said. "So I feel like it was kind of making sense back then, but even more so after this season with how much traction we've gained over the last year."

While Huff walked away from $5.4 million in the final year of his 49ers contract, Tafur noted that year carried no guarantees beyond prorated bonuses. That, plus the lack of longevity in the league, made the choice easier for Huff.

"Everybody knows football is a short-term game," he said. "You can only play until your 30s anyway."

Huff said his mother wasn't pleased, and while most of his friends expected the move, his 49ers teammates were reportedly stunned. Huff, who studied mechanical engineering at Memphis before football took over, said the startup has let him finally use that background.

"Going into the NFL, I couldn't really put my love for engineering to good use," he said. "But now I feel like since we're working with engineers on a day-to-day basis, it's just as good as actually being an engineer myself."

He's still tied to the 49ers in spirit, predicting a deep run this season with Fred Warner, George Kittle and Bosa back healthy alongside newcomer Mike Evans.

"It's going to be a great season," Huff said, "and hopefully they can bring it home."

This article originally appeared on Niners Wire: Ex-49ers edge rusher details why he retired from NFL