Why are NFL players wearing padding on helmets at training camp?

Bengals linemen, linebackers and tight ends wore Guardian Caps at training camp after the NFL required the padding for some position players this preseason.

Guardian Caps: What are they and why are NFL players wearing them? - Sactown Sports

nfl helmets training camp

Cowboys Players Wearing Strange New Helmets at Training Camp – NBC 5 Dallas-Fort Worth

Cowboys seen wearing protective, NFL mandated Guardian Caps at

NFL Introduces Guardian Caps At First Week Of Training Camp - The Sports Credential

NFL's use of Guardian padded helmet caps in camp draws support and

What's with padded helmet caps teams are wearing

Why are NFL players wearing padding on helmets at training camp

Puffy Guardian Caps Could Reduce NFL Player Concussions