NFL games might sound a lot different this season.

Seattle-based startup Vicis has been working since 2013 on a new type of football helmet that's designed to yield on contact. The result is a thud sound, instead of the violent crack players and fans are used to hearing. The softer impact means less trauma to the head, and the theory is that this will reduce the likelihood of brain injuries or concussions.

Outside of testing scenarios, Vicis's helmet, called the Zero1, has yet to make its way onto the heads of NFL players--but that's about to change. According to the company, 25 of the NFL's 32 teams have purchased stockpiles of the helmet from Vicis to distribute to their players during practices this spring.

The Safety Equipment Institute certified that the helmet met the safety thresholds established by the National Operating Committee on Standards for Athletic Equipment (NOCSAE), opening the door for its use in the NFL and NCAA. Last week, the NFL released the results of its annual lab tests that study which helmets best reduce the severity of impact to the head. Of the 33 helmets the NFL tested, the Zero1 finished first--beating out 23 helmets from Riddell and Schutt Sports, two companies that currently account for a combined 90 percent of all football helmet sales.

Vicis was founded four years ago by neurosurgeon Sam Browd, engineering professor Per Reinhall, and Dave Marver, former CEO of the Cardiac Science Corporation. The goal: Make a helmet that could reduce football's high rates of concussions and head injuries.

"We've learned a lot about how we could make the helmet better and refine it," says Marver, Vicis's CEO. The Zero1 has a soft outer shell and a core layer consisting of a series of bendable columns. These "crumple zones," inspired by and named after the parts of a car meant to crush on impact to reduce the force of a crash, allow it to absorb some of the energy of a collision.

Vicis held a mini camp with former NFL and college players earlier this year, with the athletes simulating game scenarios while wearing the helmets. "The feedback was excellent," Marver says.

Legacy companies like Riddell and Schutt and upstarts like Vicis and SG have been racing to design helmets that are safer than those already on the market. Numerous studies over the past decade have revealed the devastating long-term impact that football can have on the human brain. While football helmets have improved over the years, their design hasn't been significantly altered since the 1960s, when full face masks were added. A helmet with some give to it would be a major change. The league has been using helmets with plastic outer shells since the 1940s.

Top athletes are notoriously resistant to change in their equipment. Individual players choose what helmets they wear, so long as they meet NOCSAE performance standards, but their choices are greatly influenced by team equipment managers and trainers. Vicis's strategy has been primarily to reach out to those people within the NFL and NCAA and pitch them on the helmet's safety.

"I'm quite confident you'll see this on several NFL players this season," Marver said, though he wouldn't name names, saying that "it's up to them to reveal that."

It's worth noting that Richard Sherman, star cornerback for the hometown Seahawks, is on the company's advisory team, as are wide receiver Doug Baldwin and Kansas City Chiefs quarterback Alex Smith. Hall of Famers Jerry Rice, Tim Brown, and Roger Staubach are on the board as well.

In addition to the 25 NFL teams, Vicis says at least 20 NCAA teams will be using the helmets this year. While the company can't say which teams in either league it has sold helmets to, players for Ohio State, Ole Miss, and Auburn were spotted wearing the Zero1 during practices this spring.

Vicis's business strategy has been to target the big leagues first. Its helmet runs $1,500, making it too expensive for most high schools and youth leagues. But the startup says that within the next two years, it will release a new helmet with a more accessible price point that's specially designed for youth players.

The company has just under $30 million in funding, largely from spine surgeons, neurosurgeons, and current and former athletes.

Last year, the University of Washington and the University of Oregon agreed to have players wear the Zero1 during preseason practices. Vicis pulled the helmets when several players complained of headaches and discomfort. The company made changes to the chinstrap and the shape of the front of the helmet to address the issue.