The NFL and NFL Players Association will prohibit 10 helmet models from being worn by players this season based on the results of an annual laboratory study, the league and union said in a statement on Monday.
The models have been banned because they "perform poorly in laboratory testing, have been discontinued by the manufacturer, or were produced by companies no longer manufacturing football helmets."
Previously, NFL players could select any helmet as long as it passed current National Operating Committee on Standards for Athletic Equipment (NOCSAE) criteria for certification.
"(The NFL is) encouraged that this is an important step for player health and safety," Jeff Miller, the NFL Senior Vice President of Health and Safety Policy, told NFL.com.
Six of the models are banned immediately while the other four can continue to be used by players who wore them last season.
Approximately 200 players wore helmets last season that now would be in the prohibited category. The NFL and NFLPA expect many of those players will stop wearing those helmets immediately, per NFL Network's Tom Pelissero.
One of the prohibited models, the Riddell VSR4, has been the preferred helmet of three-time NFL MVP Tom Brady of the New England Patriots, per Jenny Vrentas of SI.com.
The helmet laboratory testing involved 34 helmet models, with a survey of helmets used by NFL teams indicating that at least 98 percent of players are wearing models that have been tested in this study.
The tests were conducted by an independent helmet testing laboratory, Biokinetics Inc. of Ottawa.