The NFL has expanded its use of guardian caps. Beyond using that from training camp, the league is expanding teams to use them for all preseason practices beyond training camp and for all contact practices during the regular season. According to NFL.com, here’s the updated layout of the Guardian Cap rules.
“The Guardian Caps that were worn during training camps last season will now be mandated at every preseason practice, as well as every regular-season and postseason practice with contact. Players at position groups where head contact is seen most are required to wear the Guardian Cap, with running backs and fullbacks joining the previously included linemen and linebackers.