Lamar Jackson wears the Douglas Rib Protector, a very common protective item among QB’s as their ribs are often exposed post-throw and defenders show no mercy (ask Drew Brees). Lamar needs that extra protection to avoid injuries. Rib protectors connect to the bottom of your shoulder pads and wrap around your body, protecting both your lower back as well as your ribs.
Get your own Douglas rib protector at Dicks for $94.