Per ESPN.com's Kevin Seifert, the NFL and the NFL Players Association agreed to eliminate certain helmet models that have "fallen short in laboratory testing" for providing proper protection.
Last year marked the first time the NFL and NFLPA began banning certain helmet models for their poor testing results. A total of 10 helmets were included on the ban list, though only six went into immediate effect.
The four remaining models were given one more year, though they were not made available to rookies.
Seifert noted the league and union approved 11 new helmet models that can be used for the 2019 season.
Jeff Miller, NFL executive vice president for health and safety initiatives, told Seifert it is "eminently doable" to convert the newly-banned models into one that is already on the approval list.
The NFL has been testing helmets since 2015 in an attempt to help protect players from head injuries and trauma. The VICISZero1 helmet is the league's most popular current model in use and includes multiple layers of protection that help reduce and slow impact forces.