NFL hopes to reduce head injuries with helmet experiment
NFL exec suggests Guardian Caps worn to protect players during practices could one day debut in games
What are those funny-looking soft caps on NFL helmets during camp?, Sports
NFL Introduces Guardian Caps At First Week Of Training Camp - The Sports Credential
The NFL Has Introduced 'Guardian Caps' to Reduce Concussions, and Made Them Mandatory. But Only for Some Positions. And Only Through the 2nd Preseason Game.
NFL Mandated Guardian Caps: Controversial Change - Sports Illustrated Seattle Seahawks News, Analysis and More
Guardian Caps: Why some NFL players are wearing them in training camps
Guardian Caps Guardian Sports
High school football looks to Guardian Cap for head safety – The Denver Post
Guardian cap' to prevent head injuries mandated for practices, CFL says
Guardian Caps NFL: What player positions are required to wear them?
Cowboys seen wearing protective, NFL mandated Guardian Caps at OTAs
If a player wanted to wear a Guardian Cap during a game, the league would prohibit it - NBC Sports
EXPLAINER: NFL using helmet caps for player safety, research